Define the public interface for content browser SiteInstance. This interface is implemented by the SiteInstanceImpl class which lives

in content\browser\site_instance.cc/.h.

Changes as part of creating a content API.

BUG=98716
TEST=No change in functionality. Hopefully it all compiles and works.
Review URL: http://codereview.chromium.org/8515027
Review URL: https://chromiumcodereview.appspot.com/9146028

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@119102 0039d316-1c4b-4281-b951-d872f2087c98

78 files changed, 587 insertions, 423 deletions

diff --git a/chrome/browser/DEPS b/chrome/browser/DEPS
index 10d70d2..3f49adc5 100644
--- a/chrome/browser/DEPS
+++ b/chrome/browser/DEPS
@@ -112,7 +112,6 @@ include_rules = [
   "+content/browser/renderer_host/test_render_view_host.h",
   "+content/browser/resource_context.h",
   "+content/browser/sensors/sensors_provider.h",
-  "+content/browser/site_instance.h",
   "+content/browser/speech/speech_input_manager.h",
   "+content/browser/speech/speech_input_preferences.h",
   "+content/browser/speech/speech_recognizer.h",
diff --git a/chrome/browser/background/background_contents_service.cc b/chrome/browser/background/background_contents_service.cc
index f1308eb..b90d52c 100644
--- a/chrome/browser/background/background_contents_service.cc
+++ b/chrome/browser/background/background_contents_service.cc
@@ -7,6 +7,7 @@
 #include "base/basictypes.h"
 #include "base/bind.h"
 #include "base/command_line.h"
+#include "base/message_loop.h"
 #include "base/string_util.h"
 #include "base/utf_string_conversions.h"
 #include "base/values.h"
@@ -27,12 +28,13 @@
 #include "chrome/common/extensions/extension.h"
 #include "chrome/common/extensions/extension_constants.h"
 #include "chrome/common/pref_names.h"
-#include "content/browser/site_instance.h"
 #include "content/public/browser/notification_service.h"
+#include "content/public/browser/site_instance.h"
 #include "content/public/browser/web_contents.h"
 #include "grit/generated_resources.h"
 #include "ui/base/l10n/l10n_util.h"
 
+using content::SiteInstance;
 using content::WebContents;
 
 namespace {
@@ -448,7 +450,7 @@ void BackgroundContentsService::LoadBackgroundContents(
   DVLOG(1) << "Loading background content url: " << url;
 
   BackgroundContents* contents = CreateBackgroundContents(
-      SiteInstance::CreateSiteInstanceForURL(profile, url),
+      SiteInstance::CreateForURL(profile, url),
       MSG_ROUTING_NONE,
       profile,
       frame_name,
diff --git a/chrome/browser/background/background_contents_service.h b/chrome/browser/background/background_contents_service.h
index b45112c..457d0ab 100644
--- a/chrome/browser/background/background_contents_service.h
+++ b/chrome/browser/background/background_contents_service.h
@@ -74,7 +74,7 @@ class BackgroundContentsService : private content::NotificationObserver,
   // A BACKGROUND_CONTENTS_OPENED notification will be generated with the passed
   // |frame_name| and |application_id| values, using the passed |profile| as the
   // Source..
-  BackgroundContents* CreateBackgroundContents(SiteInstance* site,
+  BackgroundContents* CreateBackgroundContents(content::SiteInstance* site,
                                                int route_id,
                                                Profile* profile,
                                                const string16& frame_name,
diff --git a/chrome/browser/chrome_content_browser_client.cc b/chrome/browser/chrome_content_browser_client.cc
index a13bb15..a37af6f 100644
--- a/chrome/browser/chrome_content_browser_client.cc
+++ b/chrome/browser/chrome_content_browser_client.cc
@@ -71,12 +71,12 @@
 #include "content/browser/plugin_process_host.h"
 #include "content/browser/renderer_host/render_view_host.h"
 #include "content/browser/resource_context.h"
-#include "content/browser/site_instance.h"
 #include "content/browser/ssl/ssl_cert_error_handler.h"
 #include "content/browser/ssl/ssl_client_auth_handler.h"
 #include "content/browser/worker_host/worker_process_host.h"
 #include "content/public/browser/browser_main_parts.h"
 #include "content/public/browser/render_process_host.h"
+#include "content/public/browser/site_instance.h"
 #include "content/public/browser/web_contents.h"
 #include "content/public/browser/web_contents_view.h"
 #include "grit/generated_resources.h"
@@ -133,6 +133,7 @@
 
 using content::AccessTokenStore;
 using content::BrowserThread;
+using content::SiteInstance;
 using content::WebContents;
 
 namespace {
@@ -485,20 +486,20 @@ void ChromeContentBrowserClient::SiteInstanceGotProcess(
 
   const Extension* extension =
       service->extensions()->GetExtensionOrAppByURL(ExtensionURLInfo(
-          site_instance->site()));
+          site_instance->GetSite()));
   if (!extension)
     return;
 
   service->process_map()->Insert(extension->id(),
                                  site_instance->GetProcess()->GetID(),
-                                 site_instance->id());
+                                 site_instance->GetId());
   BrowserThread::PostTask(
       BrowserThread::IO, FROM_HERE,
       base::Bind(&ExtensionInfoMap::RegisterExtensionProcess,
                  profile->GetExtensionInfoMap(),
                  extension->id(),
                  site_instance->GetProcess()->GetID(),
-                 site_instance->id()));
+                 site_instance->GetId()));
 }
 
 void ChromeContentBrowserClient::SiteInstanceDeleting(
@@ -514,20 +515,20 @@ void ChromeContentBrowserClient::SiteInstanceDeleting(
 
   const Extension* extension =
       service->extensions()->GetExtensionOrAppByURL(
-          ExtensionURLInfo(site_instance->site()));
+          ExtensionURLInfo(site_instance->GetSite()));
   if (!extension)
     return;
 
   service->process_map()->Remove(extension->id(),
                                  site_instance->GetProcess()->GetID(),
-                                 site_instance->id());
+                                 site_instance->GetId());
   BrowserThread::PostTask(
       BrowserThread::IO, FROM_HERE,
       base::Bind(&ExtensionInfoMap::UnregisterExtensionProcess,
                  profile->GetExtensionInfoMap(),
                  extension->id(),
                  site_instance->GetProcess()->GetID(),
-                 site_instance->id()));
+                 site_instance->GetId()));
 }
 
 bool ChromeContentBrowserClient::ShouldSwapProcessesForNavigation(
@@ -1346,7 +1347,7 @@ WebPreferences ChromeContentBrowserClient::GetWebkitPrefs(RenderViewHost* rvh) {
   ExtensionService* service = profile->GetExtensionService();
   if (service) {
     const Extension* extension = service->extensions()->GetByID(
-        rvh->site_instance()->site().host());
+        rvh->site_instance()->GetSite().host());
     extension_webkit_preferences::SetPreferences(
         extension, rvh->delegate()->GetRenderViewType(), &web_prefs);
   }
diff --git a/chrome/browser/chrome_content_browser_client.h b/chrome/browser/chrome_content_browser_client.h
index 9e49232..7f74616 100644
--- a/chrome/browser/chrome_content_browser_client.h
+++ b/chrome/browser/chrome_content_browser_client.h
@@ -31,8 +31,10 @@ class ChromeContentBrowserClient : public content::ContentBrowserClient {
   virtual bool IsHandledURL(const GURL& url) OVERRIDE;
   virtual bool IsSuitableHost(content::RenderProcessHost* process_host,
                               const GURL& url) OVERRIDE;
-  virtual void SiteInstanceGotProcess(SiteInstance* site_instance) OVERRIDE;
-  virtual void SiteInstanceDeleting(SiteInstance* site_instance) OVERRIDE;
+  virtual void SiteInstanceGotProcess(
+      content::SiteInstance* site_instance) OVERRIDE;
+  virtual void SiteInstanceDeleting(content::SiteInstance* site_instance)
+      OVERRIDE;
   virtual bool ShouldSwapProcessesForNavigation(const GURL& current_url,
                                                 const GURL& new_url) OVERRIDE;
   virtual std::string GetCanonicalEncodingNameByAliasName(
diff --git a/chrome/browser/chromeos/login/html_page_screen.cc b/chrome/browser/chromeos/login/html_page_screen.cc
index 5a51742..ef4f5ae 100644
--- a/chrome/browser/chromeos/login/html_page_screen.cc
+++ b/chrome/browser/chromeos/login/html_page_screen.cc
@@ -12,10 +12,11 @@
 #include "chrome/browser/chromeos/login/screen_observer.h"
 #include "chrome/browser/profiles/profile_manager.h"
 #include "content/browser/renderer_host/render_view_host.h"
-#include "content/browser/site_instance.h"
+#include "content/public/browser/site_instance.h"
 #include "googleurl/src/gurl.h"
 #include "ui/views/events/event.h"
 
+using content::SiteInstance;
 using content::WebContents;
 
 namespace chromeos {
@@ -50,8 +51,7 @@ void HTMLPageScreen::Refresh() {
   StartTimeoutTimer();
   GURL url(url_);
   Profile* profile = ProfileManager::GetDefaultProfile();
-  view()->InitDOM(profile,
-                  SiteInstance::CreateSiteInstanceForURL(profile, url));
+  view()->InitDOM(profile, SiteInstance::CreateForURL(profile, url));
   view()->SetWebContentsDelegate(this);
   view()->LoadURL(url);
 }
diff --git a/chrome/browser/chromeos/login/registration_screen.cc b/chrome/browser/chromeos/login/registration_screen.cc
index c994284..9f0d599 100644
--- a/chrome/browser/chromeos/login/registration_screen.cc
+++ b/chrome/browser/chromeos/login/registration_screen.cc
@@ -13,13 +13,14 @@
 #include "chrome/common/url_constants.h"
 #include "content/browser/child_process_security_policy.h"
 #include "content/browser/renderer_host/render_view_host.h"
-#include "content/browser/site_instance.h"
+#include "content/public/browser/site_instance.h"
 #include "content/public/browser/web_contents.h"
 #include "googleurl/src/gurl.h"
 #include "net/url_request/url_request_about_job.h"
 #include "net/url_request/url_request_filter.h"
 
 using content::OpenURLParams;
+using content::SiteInstance;
 using content::WebContents;
 
 namespace chromeos {
@@ -69,8 +70,7 @@ void RegistrationScreen::Refresh() {
   StartTimeoutTimer();
   GURL url(kRegistrationHostPageUrl);
   Profile* profile = ProfileManager::GetDefaultProfile();
-  view()->InitDOM(profile,
-                  SiteInstance::CreateSiteInstanceForURL(profile, url));
+  view()->InitDOM(profile, SiteInstance::CreateForURL(profile, url));
   view()->SetWebContentsDelegate(this);
   view()->LoadURL(url);
 }
diff --git a/chrome/browser/chromeos/login/web_page_view.cc b/chrome/browser/chromeos/login/web_page_view.cc
index 938b11b..a9690c1 100644
--- a/chrome/browser/chromeos/login/web_page_view.cc
+++ b/chrome/browser/chromeos/login/web_page_view.cc
@@ -13,6 +13,7 @@
 #include "chrome/browser/chromeos/login/rounded_rect_painter.h"
 #include "chrome/browser/profiles/profile.h"
 #include "content/browser/child_process_security_policy.h"
+#include "content/public/browser/site_instance.h"
 #include "content/public/browser/web_contents.h"
 #include "content/public/browser/web_ui.h"
 #include "content/public/common/bindings_policy.h"
@@ -29,6 +30,7 @@
 #include "ui/views/controls/throbber.h"
 
 using base::TimeDelta;
+using content::SiteInstance;
 using views::Label;
 using views::View;
 
diff --git a/chrome/browser/chromeos/login/web_page_view.h b/chrome/browser/chromeos/login/web_page_view.h
index b14b82f..90b036c 100644
--- a/chrome/browser/chromeos/login/web_page_view.h
+++ b/chrome/browser/chromeos/login/web_page_view.h
@@ -16,6 +16,7 @@
 class Profile;
 
 namespace content {
+class SiteInstance;
 class WebContentsDelegate;
 }
 
@@ -50,7 +51,7 @@ class WebPageView : public views::View {
 
   // Initialize the DOM view, creating the contents. This should be
   // called once the view has been added to a container.
-  void InitDOM(Profile* profile, SiteInstance* site_instance);
+  void InitDOM(Profile* profile, content::SiteInstance* site_instance);
 
   // Loads the given URL into the page.
   // You must have previously called Init() and SetWebContentsDelegate.
diff --git a/chrome/browser/extensions/extension_file_browser_private_api.cc b/chrome/browser/extensions/extension_file_browser_private_api.cc
index 76cfff2..cf1e1ba 100644
--- a/chrome/browser/extensions/extension_file_browser_private_api.cc
+++ b/chrome/browser/extensions/extension_file_browser_private_api.cc
@@ -34,9 +34,9 @@
 #include "chrome/common/pref_names.h"
 #include "content/browser/child_process_security_policy.h"
 #include "content/browser/renderer_host/render_view_host.h"
-#include "content/browser/site_instance.h"
 #include "content/public/browser/browser_thread.h"
 #include "content/public/browser/render_process_host.h"
+#include "content/public/browser/site_instance.h"
 #include "content/public/browser/web_contents.h"
 #include "googleurl/src/gurl.h"
 #include "grit/generated_resources.h"
@@ -50,6 +50,7 @@
 #include "webkit/fileapi/file_system_util.h"
 
 using content::BrowserThread;
+using content::SiteInstance;
 using content::WebContents;
 
 namespace {
@@ -729,7 +730,8 @@ class ExecuteTasksFileBrowserFunction::ExecuteTasksFileSystemCallbackDispatcher
         Extension::GetBaseURLFromExtensionId(target_extension_id_);
     ExtensionProcessManager* manager = profile_->GetExtensionProcessManager();
 
-    SiteInstance* site_instance = manager->GetSiteInstanceForURL(extension_url);
+    SiteInstance* site_instance = manager->GetSiteInstanceForURL(
+        extension_url);
     if (!site_instance || !site_instance->HasProcess())
       return;
     content::RenderProcessHost* process = site_instance->GetProcess();
diff --git a/chrome/browser/extensions/extension_host.cc b/chrome/browser/extensions/extension_host.cc
index c6914ea..d2d5c7d 100644
--- a/chrome/browser/extensions/extension_host.cc
+++ b/chrome/browser/extensions/extension_host.cc
@@ -32,11 +32,11 @@
 #include "chrome/common/render_messages.h"
 #include "chrome/common/url_constants.h"
 #include "content/browser/renderer_host/render_view_host.h"
-#include "content/browser/site_instance.h"
 #include "content/public/browser/content_browser_client.h"
 #include "content/public/browser/native_web_keyboard_event.h"
 #include "content/public/browser/notification_service.h"
 #include "content/public/browser/render_process_host.h"
+#include "content/public/browser/site_instance.h"
 #include "content/public/browser/web_contents.h"
 #include "content/public/browser/web_contents_view.h"
 #include "grit/browser_resources.h"
@@ -53,6 +53,7 @@
 using WebKit::WebDragOperation;
 using WebKit::WebDragOperationsMask;
 using content::OpenURLParams;
+using content::SiteInstance;
 using content::WebContents;
 
 // Helper class that rate-limits the creation of renderer processes for
diff --git a/chrome/browser/extensions/extension_host.h b/chrome/browser/extensions/extension_host.h
index 4b9263d..17701f1 100644
--- a/chrome/browser/extensions/extension_host.h
+++ b/chrome/browser/extensions/extension_host.h
@@ -31,11 +31,11 @@ class Browser;
 class Extension;
 class PrefsTabHelper;
 class RenderWidgetHostView;
-class SiteInstance;
 struct WebPreferences;
 
 namespace content {
 class RenderProcessHost;
+class SiteInstance;
 }
 
 // This class is the browser component of an extension component's RenderView.
@@ -49,7 +49,8 @@ class ExtensionHost : public content::WebContentsDelegate,
  public:
   class ProcessCreationQueue;
 
-  ExtensionHost(const Extension* extension, SiteInstance* site_instance,
+  ExtensionHost(const Extension* extension,
+                content::SiteInstance* site_instance,
                 const GURL& url, content::ViewType host_type);
   virtual ~ExtensionHost();
 
diff --git a/chrome/browser/extensions/extension_host_mac.h b/chrome/browser/extensions/extension_host_mac.h
index f2f7c1e..e755be2 100644
--- a/chrome/browser/extensions/extension_host_mac.h
+++ b/chrome/browser/extensions/extension_host_mac.h
@@ -14,7 +14,8 @@ class RenderWidgetHostView;
 // now that ExtensionHost is restructured to rely on TabContents.
 class ExtensionHostMac : public ExtensionHost {
  public:
-  ExtensionHostMac(const Extension* extension, SiteInstance* site_instance,
+  ExtensionHostMac(const Extension* extension,
+                   content::SiteInstance* site_instance,
                    const GURL& url, content::ViewType host_type) :
       ExtensionHost(extension, site_instance, url, host_type) {}
   virtual ~ExtensionHostMac();
diff --git a/chrome/browser/extensions/extension_message_service.cc b/chrome/browser/extensions/extension_message_service.cc
index 8c3ad18..097e2f6 100644
--- a/chrome/browser/extensions/extension_message_service.cc
+++ b/chrome/browser/extensions/extension_message_service.cc
@@ -18,12 +18,13 @@
 #include "chrome/common/extensions/extension_messages.h"
 #include "content/browser/child_process_security_policy.h"
 #include "content/browser/renderer_host/render_view_host.h"
-#include "content/browser/site_instance.h"
 #include "content/public/browser/notification_service.h"
 #include "content/public/browser/notification_types.h"
 #include "content/public/browser/render_process_host.h"
+#include "content/public/browser/site_instance.h"
 #include "content/public/browser/web_contents.h"
 
+using content::SiteInstance;
 using content::WebContents;
 
 // Since we have 2 ports for every channel, we just index channels by half the
diff --git a/chrome/browser/extensions/extension_process_manager.cc b/chrome/browser/extensions/extension_process_manager.cc
index 9271541..9e824db 100644
--- a/chrome/browser/extensions/extension_process_manager.cc
+++ b/chrome/browser/extensions/extension_process_manager.cc
@@ -22,17 +22,18 @@
 #include "chrome/common/extensions/extension.h"
 #include "chrome/common/url_constants.h"
 #include "content/browser/renderer_host/render_view_host.h"
-#include "content/browser/site_instance.h"
 #include "content/public/browser/browser_thread.h"
 #include "content/public/browser/notification_service.h"
 #include "content/public/browser/render_process_host.h"
 #include "content/public/browser/render_view_host_delegate.h"
+#include "content/public/browser/site_instance.h"
 #include "content/public/browser/web_contents.h"
 #include "content/public/common/renderer_preferences.h"
 
 using content::BrowserThread;
 using content::OpenURLParams;
 using content::Referrer;
+using content::SiteInstance;
 
 namespace {
 
@@ -94,7 +95,7 @@ ExtensionProcessManager* ExtensionProcessManager::Create(Profile* profile) {
 }
 
 ExtensionProcessManager::ExtensionProcessManager(Profile* profile)
-    : site_instance_(SiteInstance::CreateSiteInstance(profile)) {
+    : site_instance_(SiteInstance::Create(profile)) {
   Profile* original_profile = profile->GetOriginalProfile();
   registrar_.Add(this, chrome::NOTIFICATION_EXTENSIONS_READY,
                  content::Source<Profile>(original_profile));
@@ -280,7 +281,8 @@ void ExtensionProcessManager::UnregisterRenderViewHost(
   all_extension_views_.erase(render_view_host);
 }
 
-SiteInstance* ExtensionProcessManager::GetSiteInstanceForURL(const GURL& url) {
+SiteInstance* ExtensionProcessManager::GetSiteInstanceForURL(
+    const GURL& url) {
   return site_instance_->GetRelatedSiteInstance(url);
 }
 
@@ -303,7 +305,7 @@ bool ExtensionProcessManager::HasVisibleViews(const std::string& extension_id) {
   for (std::set<RenderViewHost*>::const_iterator it = views.begin();
        it != views.end(); ++it) {
     const RenderViewHost* host = *it;
-    if (host->site_instance()->site().host() == extension_id &&
+    if (host->site_instance()->GetSite().host() == extension_id &&
         host->delegate()->GetRenderViewType() !=
         chrome::VIEW_TYPE_EXTENSION_BACKGROUND_PAGE) {
       return true;
diff --git a/chrome/browser/extensions/extension_process_manager.h b/chrome/browser/extensions/extension_process_manager.h
index 743fd55..41f7c60 100644
--- a/chrome/browser/extensions/extension_process_manager.h
+++ b/chrome/browser/extensions/extension_process_manager.h
@@ -22,7 +22,10 @@ class ExtensionHost;
 class GURL;
 class Profile;
 class RenderViewHost;
+
+namespace content {
 class SiteInstance;
+};
 
 // Manages dynamic state of running Chromium extensions. There is one instance
 // of this class per Profile. OTR Profiles have a separate instance that keeps
@@ -69,7 +72,7 @@ class ExtensionProcessManager : public content::NotificationObserver {
   // Returns the SiteInstance that the given URL belongs to.
   // TODO(aa): This only returns correct results for extensions and packaged
   // apps, not hosted apps.
-  virtual SiteInstance* GetSiteInstanceForURL(const GURL& url);
+  virtual content::SiteInstance* GetSiteInstanceForURL(const GURL& url);
 
   // Registers a RenderViewHost as hosting a given extension.
   void RegisterRenderViewHost(RenderViewHost* render_view_host,
@@ -124,7 +127,7 @@ class ExtensionProcessManager : public content::NotificationObserver {
   // A SiteInstance related to the SiteInstance for all extensions in
   // this profile.  We create it in such a way that a new
   // browsing instance is created.  This controls process grouping.
-  scoped_refptr<SiteInstance> site_instance_;
+  scoped_refptr<content::SiteInstance> site_instance_;
 
  private:
   // Contains all extension-related RenderViewHost instances for all extensions.
diff --git a/chrome/browser/extensions/extension_process_manager_unittest.cc b/chrome/browser/extensions/extension_process_manager_unittest.cc
index 025fb4c1..bdd8d96 100644
--- a/chrome/browser/extensions/extension_process_manager_unittest.cc
+++ b/chrome/browser/extensions/extension_process_manager_unittest.cc
@@ -5,10 +5,13 @@
 #include "chrome/browser/extensions/extension_process_manager.h"
 #include "chrome/browser/extensions/extension_error_reporter.h"
 #include "chrome/test/base/testing_profile.h"
-#include "content/browser/site_instance.h"
+#include "content/public/browser/render_process_host.h"
+#include "content/public/browser/site_instance.h"
 #include "testing/gtest/include/gtest/gtest.h"
 #include "testing/platform_test.h"
 
+using content::SiteInstance;
+
 namespace {
 
 // make the test a PlatformTest to setup autorelease pools properly on mac
diff --git a/chrome/browser/extensions/isolated_app_browsertest.cc b/chrome/browser/extensions/isolated_app_browsertest.cc
index 43941c6..dc5bc2b 100644
--- a/chrome/browser/extensions/isolated_app_browsertest.cc
+++ b/chrome/browser/extensions/isolated_app_browsertest.cc
@@ -13,9 +13,9 @@
 #include "chrome/common/chrome_switches.h"
 #include "chrome/common/url_constants.h"
 #include "chrome/test/base/ui_test_utils.h"
-#include "content/browser/site_instance.h"
 #include "content/browser/renderer_host/render_view_host.h"
 #include "content/public/browser/render_process_host.h"
+#include "content/public/browser/site_instance.h"
 #include "content/public/browser/web_contents.h"
 #include "net/base/mock_host_resolver.h"
 
diff --git a/chrome/browser/notifications/balloon_host.cc b/chrome/browser/notifications/balloon_host.cc
index e5590f9..aa2eb47 100644
--- a/chrome/browser/notifications/balloon_host.cc
+++ b/chrome/browser/notifications/balloon_host.cc
@@ -16,17 +16,18 @@
 #include "chrome/common/url_constants.h"
 #include "chrome/common/chrome_view_type.h"
 #include "content/browser/renderer_host/render_view_host.h"
-#include "content/browser/site_instance.h"
 #include "content/public/browser/navigation_controller.h"
 #include "content/public/browser/notification_service.h"
 #include "content/public/browser/notification_source.h"
 #include "content/public/browser/render_process_host.h"
+#include "content/public/browser/site_instance.h"
 #include "content/public/browser/web_contents.h"
 #include "content/public/common/bindings_policy.h"
 #include "content/public/common/renderer_preferences.h"
 #include "ipc/ipc_message.h"
 #include "webkit/glue/webpreferences.h"
 
+using content::SiteInstance;
 using content::WebContents;
 
 BalloonHost::BalloonHost(Balloon* balloon)
@@ -36,7 +37,7 @@ BalloonHost::BalloonHost(Balloon* balloon)
       enable_web_ui_(false),
       ALLOW_THIS_IN_INITIALIZER_LIST(
           extension_function_dispatcher_(balloon_->profile(), this)) {
-  site_instance_ = SiteInstance::CreateSiteInstanceForURL(
+  site_instance_ = SiteInstance::CreateForURL(
       balloon_->profile(), balloon_->notification().content_url());
 }
 
diff --git a/chrome/browser/notifications/balloon_host.h b/chrome/browser/notifications/balloon_host.h
index 710961a5..f05d53e 100644
--- a/chrome/browser/notifications/balloon_host.h
+++ b/chrome/browser/notifications/balloon_host.h
@@ -19,7 +19,10 @@
 
 class Balloon;
 class Browser;
+
+namespace content {
 class SiteInstance;
+};
 
 class BalloonHost : public content::WebContentsDelegate,
                     public content::WebContentsObserver,
@@ -89,7 +92,7 @@ class BalloonHost : public content::WebContentsDelegate,
   bool should_notify_on_disconnect_;
 
   // Site instance for the balloon/profile, to be used for opening new links.
-  scoped_refptr<SiteInstance> site_instance_;
+  scoped_refptr<content::SiteInstance> site_instance_;
 
   // A flag to enable Web UI.
   bool enable_web_ui_;
diff --git a/chrome/browser/renderer_host/chrome_render_view_host_observer.cc b/chrome/browser/renderer_host/chrome_render_view_host_observer.cc
index adefdb6..26cd431 100644
--- a/chrome/browser/renderer_host/chrome_render_view_host_observer.cc
+++ b/chrome/browser/renderer_host/chrome_render_view_host_observer.cc
@@ -16,9 +16,11 @@
 #include "chrome/common/url_constants.h"
 #include "content/browser/child_process_security_policy.h"
 #include "content/browser/renderer_host/render_view_host.h"
-#include "content/browser/site_instance.h"
 #include "content/public/browser/notification_service.h"
 #include "content/public/browser/render_view_host_delegate.h"
+#include "content/public/browser/site_instance.h"
+
+using content::SiteInstance;
 
 ChromeRenderViewHostObserver::ChromeRenderViewHostObserver(
     RenderViewHost* render_view_host, chrome_browser_net::Predictor* predictor)
@@ -133,7 +135,7 @@ const Extension* ChromeRenderViewHostObserver::GetExtension() {
   // (excluding bookmark apps) will have a chrome-extension:// URL for their
   // site, so we can ignore that wrinkle here.
   SiteInstance* site_instance = render_view_host()->site_instance();
-  const GURL& site = site_instance->site();
+  const GURL& site = site_instance->GetSite();
 
   if (!site.SchemeIs(chrome::kExtensionScheme))
     return NULL;
diff --git a/chrome/browser/tab_contents/background_contents.cc b/chrome/browser/tab_contents/background_contents.cc
index f799a9c..16d3dfe 100644
--- a/chrome/browser/tab_contents/background_contents.cc
+++ b/chrome/browser/tab_contents/background_contents.cc
@@ -14,11 +14,12 @@
 #include "chrome/common/url_constants.h"
 #include "chrome/common/chrome_view_type.h"
 #include "content/browser/renderer_host/render_view_host.h"
-#include "content/browser/site_instance.h"
 #include "content/public/browser/notification_service.h"
+#include "content/public/browser/site_instance.h"
 #include "content/public/browser/web_contents.h"
 #include "ui/gfx/rect.h"
 
+using content::SiteInstance;
 using content::WebContents;
 
 BackgroundContents::BackgroundContents(SiteInstance* site_instance,
diff --git a/chrome/browser/tab_contents/background_contents.h b/chrome/browser/tab_contents/background_contents.h
index 675281e..6f3b9cd 100644
--- a/chrome/browser/tab_contents/background_contents.h
+++ b/chrome/browser/tab_contents/background_contents.h
@@ -16,7 +16,10 @@
 #include "webkit/glue/window_open_disposition.h"
 
 class Profile;
+
+namespace content {
 class SiteInstance;
+};
 
 // This class consumes TabContents. It can host a renderer, but does not
 // have any visible display.
@@ -38,7 +41,7 @@ class BackgroundContents : public content::WebContentsDelegate,
     virtual ~Delegate() {}
   };
 
-  BackgroundContents(SiteInstance* site_instance,
+  BackgroundContents(content::SiteInstance* site_instance,
                      int routing_id,
                      Delegate* delegate);
   virtual ~BackgroundContents();
diff --git a/chrome/browser/tab_contents/tab_util.cc b/chrome/browser/tab_contents/tab_util.cc
index 296df65..09461bee 100644
--- a/chrome/browser/tab_contents/tab_util.cc
+++ b/chrome/browser/tab_contents/tab_util.cc
@@ -9,11 +9,12 @@
 #include "chrome/browser/ui/webui/chrome_web_ui_factory.h"
 #include "chrome/common/chrome_switches.h"
 #include "content/browser/renderer_host/render_view_host.h"
-#include "content/browser/site_instance.h"
 #include "content/public/browser/render_view_host_delegate.h"
+#include "content/public/browser/site_instance.h"
 #include "content/public/browser/web_contents.h"
 #include "googleurl/src/gurl.h"
 
+using content::SiteInstance;
 using content::WebContents;
 
 namespace tab_util {
@@ -38,7 +39,7 @@ SiteInstance* GetSiteInstanceForNewTab(WebContents* source_contents,
   if (ChromeWebUIFactory::GetInstance()->UseWebUIForURL(profile, url) ||
       (service &&
        service->extensions()->GetHostedAppByURL(ExtensionURLInfo(url)))) {
-    return SiteInstance::CreateSiteInstanceForURL(profile, url);
+    return SiteInstance::CreateForURL(profile, url);
   }
 
   if (!source_contents)
diff --git a/chrome/browser/tab_contents/tab_util.h b/chrome/browser/tab_contents/tab_util.h
index 0b14f55..5866e02 100644
--- a/chrome/browser/tab_contents/tab_util.h
+++ b/chrome/browser/tab_contents/tab_util.h
@@ -8,8 +8,9 @@
 
 class GURL;
 class Profile;
-class SiteInstance;
+
 namespace content {
+class SiteInstance;
 class WebContents;
 }
 
@@ -24,9 +25,10 @@ content::WebContents* GetWebContentsByID(int render_process_id,
 // Returns a new SiteInstance for WebUI and app URLs. Returns the SiteInstance
 // for |source_contents| if it represents the same website as |url|. Returns
 // NULL otherwise.
-SiteInstance* GetSiteInstanceForNewTab(content::WebContents* source_contents,
-                                       Profile* profile,
-                                       const GURL& url);
+content::SiteInstance* GetSiteInstanceForNewTab(
+    content::WebContents* source_contents,
+    Profile* profile,
+    const GURL& url);
 
 }  // namespace tab_util
 
diff --git a/chrome/browser/tabs/default_tab_handler.cc b/chrome/browser/tabs/default_tab_handler.cc
index d7f7ec3..f8f46d70 100644
--- a/chrome/browser/tabs/default_tab_handler.cc
+++ b/chrome/browser/tabs/default_tab_handler.cc
@@ -7,6 +7,8 @@
 #include "chrome/browser/tabs/tab_strip_model.h"
 #include "chrome/browser/ui/browser.h"
 
+using content::SiteInstance;
+
 ////////////////////////////////////////////////////////////////////////////////
 // DefaultTabHandler, public:
 
diff --git a/chrome/browser/tabs/default_tab_handler.h b/chrome/browser/tabs/default_tab_handler.h
index d5e7e8d..a866a4a 100644
--- a/chrome/browser/tabs/default_tab_handler.h
+++ b/chrome/browser/tabs/default_tab_handler.h
@@ -42,7 +42,7 @@ class DefaultTabHandler : public TabHandler,
       Profile* profile,
       content::PageTransition transition,
       bool defer_load,
-      SiteInstance* instance) const OVERRIDE;
+      content::SiteInstance* instance) const OVERRIDE;
   virtual bool CanDuplicateContentsAt(int index) OVERRIDE;
   virtual void DuplicateContentsAt(int index) OVERRIDE;
   virtual void CloseFrameAfterDragSession() OVERRIDE;
diff --git a/chrome/browser/tabs/tab_strip_model_delegate.h b/chrome/browser/tabs/tab_strip_model_delegate.h
index 1c8e00e..0f552fd 100644
--- a/chrome/browser/tabs/tab_strip_model_delegate.h
+++ b/chrome/browser/tabs/tab_strip_model_delegate.h
@@ -14,10 +14,10 @@ class Browser;
 class DockInfo;
 class GURL;
 class Profile;
-class SiteInstance;
 class TabContents;
 class TabContentsWrapper;
 namespace content {
+class SiteInstance;
 struct Referrer;
 }
 namespace gfx {
@@ -72,7 +72,7 @@ class TabStripModelDelegate {
       Profile* profile,
       content::PageTransition transition,
       bool defer_load,
-      SiteInstance* instance) const = 0;
+      content::SiteInstance* instance) const = 0;
 
   // Returns whether some contents can be duplicated.
   virtual bool CanDuplicateContentsAt(int index) = 0;
diff --git a/chrome/browser/tabs/tab_strip_model_unittest.cc b/chrome/browser/tabs/tab_strip_model_unittest.cc
index 3a12732..681cc34 100644
--- a/chrome/browser/tabs/tab_strip_model_unittest.cc
+++ b/chrome/browser/tabs/tab_strip_model_unittest.cc
@@ -43,6 +43,7 @@
 
 using content::BrowserThread;
 using content::NavigationController;
+using content::SiteInstance;
 using content::WebContents;
 using testing::_;
 
diff --git a/chrome/browser/tabs/test_tab_strip_model_delegate.cc b/chrome/browser/tabs/test_tab_strip_model_delegate.cc
index f7955f6..f87201c 100644
--- a/chrome/browser/tabs/test_tab_strip_model_delegate.cc
+++ b/chrome/browser/tabs/test_tab_strip_model_delegate.cc
@@ -9,6 +9,8 @@
 #include "chrome/browser/ui/tabs/dock_info.h"
 #include "ui/gfx/rect.h"
 
+using content::SiteInstance;
+
 TestTabStripModelDelegate::TestTabStripModelDelegate() {
 }
 
diff --git a/chrome/browser/tabs/test_tab_strip_model_delegate.h b/chrome/browser/tabs/test_tab_strip_model_delegate.h
index 15f0b5c..486ea56 100644
--- a/chrome/browser/tabs/test_tab_strip_model_delegate.h
+++ b/chrome/browser/tabs/test_tab_strip_model_delegate.h
@@ -31,7 +31,7 @@ class TestTabStripModelDelegate : public TabStripModelDelegate {
       Profile* profile,
       content::PageTransition transition,
       bool defer_load,
-      SiteInstance* instance) const OVERRIDE;
+      content::SiteInstance* instance) const OVERRIDE;
   virtual bool CanDuplicateContentsAt(int index) OVERRIDE;
   virtual void DuplicateContentsAt(int index) OVERRIDE;
   virtual void CloseFrameAfterDragSession() OVERRIDE;
diff --git a/chrome/browser/ui/browser.cc b/chrome/browser/ui/browser.cc
index 731cfb7..ecfcaa5 100644
--- a/chrome/browser/ui/browser.cc
+++ b/chrome/browser/ui/browser.cc
@@ -148,7 +148,6 @@
 #include "content/browser/child_process_security_policy.h"
 #include "content/browser/host_zoom_map.h"
 #include "content/browser/renderer_host/render_view_host.h"
-#include "content/browser/site_instance.h"
 #include "content/browser/tab_contents/interstitial_page.h"
 #include "content/public/browser/devtools_manager.h"
 #include "content/public/browser/download_item.h"
@@ -159,6 +158,7 @@
 #include "content/public/browser/notification_details.h"
 #include "content/public/browser/notification_service.h"
 #include "content/public/browser/plugin_service.h"
+#include "content/public/browser/site_instance.h"
 #include "content/public/browser/user_metrics.h"
 #include "content/public/browser/web_contents.h"
 #include "content/public/browser/web_contents_view.h"
@@ -221,6 +221,7 @@ using content::NavigationEntry;
 using content::OpenURLParams;
 using content::PluginService;
 using content::Referrer;
+using content::SiteInstance;
 using content::SSLStatus;
 using content::UserMetricsAction;
 using content::WebContents;
diff --git a/chrome/browser/ui/browser.h b/chrome/browser/ui/browser.h
index 60abc8f..89151e2 100644
--- a/chrome/browser/ui/browser.h
+++ b/chrome/browser/ui/browser.h
@@ -774,7 +774,7 @@ class Browser : public TabHandlerDelegate,
   // all its supporting objects and observers.
   static TabContentsWrapper*
       TabContentsFactory(Profile* profile,
-                         SiteInstance* site_instance,
+                         content::SiteInstance* site_instance,
                          int routing_id,
                          const content::WebContents* base_web_contents,
                          SessionStorageNamespace* session_storage_namespace);
@@ -800,7 +800,7 @@ class Browser : public TabHandlerDelegate,
       Profile* profile,
       content::PageTransition transition,
       bool defer_load,
-      SiteInstance* instance) const;
+      content::SiteInstance* instance) const;
   virtual bool CanDuplicateContentsAt(int index);
   virtual void DuplicateContentsAt(int index);
   virtual void CloseFrameAfterDragSession();
@@ -1293,7 +1293,7 @@ class Browser : public TabHandlerDelegate,
   // Creates a BackgroundContents if appropriate; return true if one was
   // created.
   bool MaybeCreateBackgroundContents(int route_id,
-                                     SiteInstance* site,
+                                     content::SiteInstance* site,
                                      const GURL& opener_url,
                                      const string16& frame_name);
 
diff --git a/chrome/browser/ui/browser_navigator.cc b/chrome/browser/ui/browser_navigator.cc
index c8fa8a9..1c099d6 100644
--- a/chrome/browser/ui/browser_navigator.cc
+++ b/chrome/browser/ui/browser_navigator.cc
@@ -32,7 +32,6 @@
 #include "chrome/common/url_constants.h"
 #include "content/browser/browser_url_handler.h"
 #include "content/browser/renderer_host/render_view_host.h"
-#include "content/browser/site_instance.h"
 #include "content/public/browser/notification_service.h"
 #include "content/public/browser/render_view_host_delegate.h"
 #include "content/public/browser/web_contents.h"
diff --git a/chrome/browser/ui/cocoa/fullscreen_exit_bubble_controller_unittest.mm b/chrome/browser/ui/cocoa/fullscreen_exit_bubble_controller_unittest.mm
index 0bdb82e..1228f97 100644
--- a/chrome/browser/ui/cocoa/fullscreen_exit_bubble_controller_unittest.mm
+++ b/chrome/browser/ui/cocoa/fullscreen_exit_bubble_controller_unittest.mm
@@ -12,12 +12,13 @@
 #include "chrome/browser/ui/cocoa/cocoa_profile_test.h"
 #include "chrome/common/chrome_notification_types.h"
 #include "chrome/test/base/ui_test_utils.h"
-#include "content/browser/site_instance.h"
 #include "content/public/browser/notification_service.h"
+#include "content/public/browser/site_instance.h"
 #include "content/public/browser/web_contents.h"
 #include "testing/gtest_mac.h"
 #include "ui/base/accelerators/accelerator_cocoa.h"
 
+using content::SiteInstance;
 using content::WebContents;
 
 @interface FullscreenExitBubbleController(JustForTesting)
@@ -47,7 +48,7 @@ class FullscreenExitBubbleControllerTest : public CocoaProfileTest {
     CocoaProfileTest::SetUp();
     ASSERT_TRUE(profile());
 
-    site_instance_ = SiteInstance::CreateSiteInstance(profile());
+    site_instance_ = SiteInstance::Create(profile());
     controller_.reset(
         [[FullscreenExitBubbleController alloc] initWithOwner:nil
                                                       browser:browser()
diff --git a/chrome/browser/ui/cocoa/tabpose_window_unittest.mm b/chrome/browser/ui/cocoa/tabpose_window_unittest.mm
index e0263fa..82b7ccb 100644
--- a/chrome/browser/ui/cocoa/tabpose_window_unittest.mm
+++ b/chrome/browser/ui/cocoa/tabpose_window_unittest.mm
@@ -8,16 +8,18 @@
 #import "chrome/browser/ui/browser_window.h"
 #include "chrome/browser/ui/cocoa/cocoa_profile_test.h"
 #include "chrome/browser/ui/tab_contents/tab_contents_wrapper.h"
-#include "content/browser/site_instance.h"
+#include "content/public/browser/site_instance.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
+using content::SiteInstance;
+
 class TabposeWindowTest : public CocoaProfileTest {
  public:
   virtual void SetUp() {
     CocoaProfileTest::SetUp();
     ASSERT_TRUE(profile());
 
-    site_instance_ = SiteInstance::CreateSiteInstance(profile());
+    site_instance_ = SiteInstance::Create(profile());
   }
 
   void AppendTabToStrip() {
diff --git a/chrome/browser/ui/cocoa/tabs/tab_strip_controller_unittest.mm b/chrome/browser/ui/cocoa/tabs/tab_strip_controller_unittest.mm
index 173b4e6..063a815 100644
--- a/chrome/browser/ui/cocoa/tabs/tab_strip_controller_unittest.mm
+++ b/chrome/browser/ui/cocoa/tabs/tab_strip_controller_unittest.mm
@@ -14,11 +14,12 @@
 #import "chrome/browser/ui/cocoa/tabs/tab_view.h"
 #import "chrome/browser/ui/cocoa/tabs/tab_controller.h"
 #include "chrome/browser/ui/tab_contents/tab_contents_wrapper.h"
-#include "content/browser/site_instance.h"
+#include "content/public/browser/site_instance.h"
 #include "content/public/browser/web_contents.h"
 #include "testing/gtest/include/gtest/gtest.h"
 #include "testing/platform_test.h"
 
+using content::SiteInstance;
 using content::WebContents;
 
 @interface TestTabStripControllerDelegate
@@ -168,7 +169,7 @@ class TabStripControllerTest : public CocoaProfileTest {
 // the tab strip.
 TEST_F(TabStripControllerTest, AddRemoveTabs) {
   EXPECT_TRUE(model_->empty());
-  SiteInstance* instance = SiteInstance::CreateSiteInstance(profile());
+  SiteInstance* instance = SiteInstance::Create(profile());
   TabContentsWrapper* tab_contents =
       Browser::TabContentsFactory(profile(), instance,
           MSG_ROUTING_NONE, NULL, NULL);
@@ -192,14 +193,14 @@ TEST_F(TabStripControllerTest, Notifications) {
 
 TEST_F(TabStripControllerTest, CorrectToolTipText) {
   // Create tab 1.
-  SiteInstance* instance = SiteInstance::CreateSiteInstance(profile());
+  SiteInstance* instance = SiteInstance::Create(profile());
   TabContentsWrapper* tab_contents =
   Browser::TabContentsFactory(profile(), instance,
                               MSG_ROUTING_NONE, NULL, NULL);
   model_->AppendTabContents(tab_contents, true);
 
   // Create tab 2.
-  SiteInstance* instance2 = SiteInstance::CreateSiteInstance(profile());
+  SiteInstance* instance2 = SiteInstance::Create(profile());
   TabContentsWrapper* tab_contents2 =
   Browser::TabContentsFactory(profile(), instance2,
                               MSG_ROUTING_NONE, NULL, NULL);
diff --git a/chrome/browser/ui/views/dom_view.cc b/chrome/browser/ui/views/dom_view.cc
index 87aaa45..9335a714 100644
--- a/chrome/browser/ui/views/dom_view.cc
+++ b/chrome/browser/ui/views/dom_view.cc
@@ -7,9 +7,11 @@
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/renderer_preferences_util.h"
 #include "chrome/browser/ui/views/tab_contents/tab_contents_view_views.h"
+#include "content/public/browser/site_instance.h"
 #include "content/public/browser/web_contents.h"
 #include "ui/views/focus/focus_manager.h"
 
+using content::SiteInstance;
 using content::WebContents;
 
 // static
diff --git a/chrome/browser/ui/views/dom_view.h b/chrome/browser/ui/views/dom_view.h
index f9d45e9..e9b5f4b 100644
--- a/chrome/browser/ui/views/dom_view.h
+++ b/chrome/browser/ui/views/dom_view.h
@@ -16,7 +16,10 @@
 #include "ui/views/events/event.h"
 
 class Profile;
+
+namespace content {
 class SiteInstance;
+};
 
 class DOMView : public views::NativeViewHost {
  public:
@@ -34,7 +37,7 @@ class DOMView : public views::NativeViewHost {
   //
   // If |instance| is not null, then the view will be loaded in the same
   // process as the given instance.
-  bool Init(Profile* profile, SiteInstance* instance);
+  bool Init(Profile* profile, content::SiteInstance* instance);
 
   // Loads the given URL into the page. You must have previously called Init().
   void LoadURL(const GURL& url);
@@ -57,7 +60,7 @@ class DOMView : public views::NativeViewHost {
   // Returns new allocated TabContents instance, caller is responsible deleting.
   // Override in derived classes to replace TabContents with derivative.
   virtual content::WebContents* CreateTabContents(
-      Profile* profile, SiteInstance* instance);
+    Profile* profile, content::SiteInstance* instance);
 
   scoped_ptr<TabContentsWrapper> dom_contents_;
 
diff --git a/chrome/browser/ui/virtual_keyboard/virtual_keyboard_manager.cc b/chrome/browser/ui/virtual_keyboard/virtual_keyboard_manager.cc
index 1e69bcd..a10b088 100644
--- a/chrome/browser/ui/virtual_keyboard/virtual_keyboard_manager.cc
+++ b/chrome/browser/ui/virtual_keyboard/virtual_keyboard_manager.cc
@@ -19,8 +19,8 @@
 #include "chrome/common/chrome_notification_types.h"
 #include "chrome/common/extensions/extension_messages.h"
 #include "chrome/common/url_constants.h"
-#include "content/browser/site_instance.h"
 #include "content/public/browser/notification_service.h"
+#include "content/public/browser/site_instance.h"
 #include "content/public/browser/web_contents_observer.h"
 #include "ui/base/animation/animation_delegate.h"
 #include "ui/base/animation/slide_animation.h"
@@ -193,8 +193,7 @@ KeyboardWidget::KeyboardWidget()
 
   // Setup the DOM view to host the keyboard.
   Profile* profile = ProfileManager::GetDefaultProfile();
-  dom_view_->Init(profile,
-      SiteInstance::CreateSiteInstanceForURL(profile, keyboard_url_));
+  dom_view_->Init(profile, SiteInstance::CreateForURL(profile, keyboard_url_));
   dom_view_->LoadURL(keyboard_url_);
   dom_view_->SetVisible(true);
   SetContentsView(dom_view_);
diff --git a/chrome/browser/ui/webui/options/extension_settings_handler.cc b/chrome/browser/ui/webui/options/extension_settings_handler.cc
index 9229c71..cf99cb2 100644
--- a/chrome/browser/ui/webui/options/extension_settings_handler.cc
+++ b/chrome/browser/ui/webui/options/extension_settings_handler.cc
@@ -32,7 +32,6 @@
 #include "chrome/common/pref_names.h"
 #include "chrome/common/url_constants.h"
 #include "content/browser/renderer_host/render_view_host.h"
-#include "content/browser/site_instance.h"
 #include "content/public/browser/notification_service.h"
 #include "content/public/browser/notification_types.h"
 #include "content/public/browser/web_contents.h"
diff --git a/chrome/browser/ui/webui/web_ui_unittest.cc b/chrome/browser/ui/webui/web_ui_unittest.cc
index fc9bbc8..2d80485 100644
--- a/chrome/browser/ui/webui/web_ui_unittest.cc
+++ b/chrome/browser/ui/webui/web_ui_unittest.cc
@@ -8,14 +8,15 @@
 #include "chrome/browser/ui/tab_contents/test_tab_contents_wrapper.h"
 #include "chrome/common/url_constants.h"
 #include "chrome/test/base/testing_profile.h"
-#include "content/browser/site_instance.h"
 #include "content/browser/tab_contents/test_tab_contents.h"
 #include "content/public/browser/navigation_controller.h"
+#include "content/public/browser/site_instance.h"
 #include "content/test/test_browser_thread.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 using content::BrowserThread;
 using content::NavigationController;
+using content::SiteInstance;
 using content::WebContents;
 
 class WebUITest : public TabContentsWrapperTestHarness {
@@ -170,7 +171,7 @@ TEST_F(WebUITest, FocusOnNavigate) {
   // Setup.  |tc| will be used to track when we try to focus the location bar.
   TabContentsForFocusTest* tc = new TabContentsForFocusTest(
       contents()->GetBrowserContext(),
-      SiteInstance::CreateSiteInstance(contents()->GetBrowserContext()));
+      SiteInstance::Create(contents()->GetBrowserContext()));
   tc->GetController().CopyStateFrom(controller());
   SetContents(tc);
   int page_id = 200;
diff --git a/content/browser/browsing_instance.cc b/content/browser/browsing_instance.cc
index 4809dd76..a03d873 100644
--- a/content/browser/browsing_instance.cc
+++ b/content/browser/browsing_instance.cc
@@ -6,13 +6,15 @@
 
 #include "base/command_line.h"
 #include "base/logging.h"
-#include "content/browser/site_instance.h"
+#include "content/browser/site_instance_impl.h"
 #include "content/public/browser/browser_context.h"
 #include "content/public/browser/content_browser_client.h"
 #include "content/public/browser/web_ui_factory.h"
 #include "content/public/common/content_switches.h"
 #include "content/public/common/url_constants.h"
 
+using content::SiteInstance;
+
 // static
 base::LazyInstance<
     BrowsingInstance::ContextSiteInstanceMap,
@@ -56,8 +58,8 @@ bool BrowsingInstance::ShouldUseProcessPerSite(const GURL& url) {
 
 BrowsingInstance::SiteInstanceMap* BrowsingInstance::GetSiteInstanceMap(
     content::BrowserContext* browser_context, const GURL& url) {
-  if (!ShouldUseProcessPerSite(SiteInstance::GetEffectiveURL(browser_context,
-                                                             url))) {
+  if (!ShouldUseProcessPerSite(
+      SiteInstanceImpl::GetEffectiveURL(browser_context, url))) {
     // Not using process-per-site, so use a map specific to this instance.
     return &site_instance_map_;
   }
@@ -69,7 +71,7 @@ BrowsingInstance::SiteInstanceMap* BrowsingInstance::GetSiteInstanceMap(
 
 bool BrowsingInstance::HasSiteInstance(const GURL& url) {
   std::string site =
-      SiteInstance::GetSiteForURL(browser_context_, url)
+      SiteInstanceImpl::GetSiteForURL(browser_context_, url)
           .possibly_invalid_spec();
 
   SiteInstanceMap* map = GetSiteInstanceMap(browser_context_, url);
@@ -79,7 +81,7 @@ bool BrowsingInstance::HasSiteInstance(const GURL& url) {
 
 SiteInstance* BrowsingInstance::GetSiteInstanceForURL(const GURL& url) {
   std::string site =
-      SiteInstance::GetSiteForURL(browser_context_, url)
+      SiteInstanceImpl::GetSiteForURL(browser_context_, url)
           .possibly_invalid_spec();
 
   SiteInstanceMap* map = GetSiteInstanceMap(browser_context_, url);
@@ -89,7 +91,7 @@ SiteInstance* BrowsingInstance::GetSiteInstanceForURL(const GURL& url) {
   }
 
   // No current SiteInstance for this site, so let's create one.
-  SiteInstance* instance = new SiteInstance(this);
+  SiteInstanceImpl* instance = new SiteInstanceImpl(this);
 
   // Set the site of this new SiteInstance, which will register it with us.
   instance->SetSite(url);
@@ -97,9 +99,10 @@ SiteInstance* BrowsingInstance::GetSiteInstanceForURL(const GURL& url) {
 }
 
 void BrowsingInstance::RegisterSiteInstance(SiteInstance* site_instance) {
-  DCHECK(site_instance->browsing_instance_ == this);
-  DCHECK(site_instance->has_site());
-  std::string site = site_instance->site().possibly_invalid_spec();
+  DCHECK(static_cast<SiteInstanceImpl*>(site_instance)->
+         browsing_instance_ == this);
+  DCHECK(static_cast<SiteInstanceImpl*>(site_instance)->HasSite());
+  std::string site = site_instance->GetSite().possibly_invalid_spec();
 
   // Only register if we don't have a SiteInstance for this site already.
   // It's possible to have two SiteInstances point to the same site if two
@@ -107,7 +110,7 @@ void BrowsingInstance::RegisterSiteInstance(SiteInstance* site_instance) {
   // register them until DidNavigate.)  If there is a previously existing
   // SiteInstance for this site, we just won't register the new one.
   SiteInstanceMap* map = GetSiteInstanceMap(browser_context_,
-                                            site_instance->site());
+                                            site_instance->GetSite());
   SiteInstanceMap::iterator i = map->find(site);
   if (i == map->end()) {
     // Not previously registered, so register it.
@@ -116,9 +119,10 @@ void BrowsingInstance::RegisterSiteInstance(SiteInstance* site_instance) {
 }
 
 void BrowsingInstance::UnregisterSiteInstance(SiteInstance* site_instance) {
-  DCHECK(site_instance->browsing_instance_ == this);
-  DCHECK(site_instance->has_site());
-  std::string site = site_instance->site().possibly_invalid_spec();
+  DCHECK(static_cast<SiteInstanceImpl*>(site_instance)->
+         browsing_instance_ == this);
+  DCHECK(static_cast<SiteInstanceImpl*>(site_instance)->HasSite());
+  std::string site = site_instance->GetSite().possibly_invalid_spec();
 
   // Only unregister the SiteInstance if it is the same one that is registered
   // for the site.  (It might have been an unregistered SiteInstance.  See the
@@ -139,9 +143,10 @@ void BrowsingInstance::UnregisterSiteInstance(SiteInstance* site_instance) {
   }
 }
 
-bool BrowsingInstance::RemoveSiteInstanceFromMap(SiteInstanceMap* map,
-                                                 const std::string& site,
-                                                 SiteInstance* site_instance) {
+bool BrowsingInstance::RemoveSiteInstanceFromMap(
+    SiteInstanceMap* map,
+    const std::string& site,
+    SiteInstance* site_instance) {
   SiteInstanceMap::iterator i = map->find(site);
   if (i != map->end() && i->second == site_instance) {
     // Matches, so erase it.
diff --git a/content/browser/browsing_instance.h b/content/browser/browsing_instance.h
index d3baf8a..f32b3d5 100644
--- a/content/browser/browsing_instance.h
+++ b/content/browser/browsing_instance.h
@@ -12,10 +12,11 @@
 #include "content/common/content_export.h"
 
 class GURL;
-class SiteInstance;
+class SiteInstanceImpl;
 
 namespace content {
 class BrowserContext;
+class SiteInstance;
 }
 
 ///////////////////////////////////////////////////////////////////////////////
@@ -80,19 +81,20 @@ class CONTENT_EXPORT BrowsingInstance
   // Get the SiteInstance responsible for rendering the given URL.  Should
   // create a new one if necessary, but should not create more than one
   // SiteInstance per site.
-  SiteInstance* GetSiteInstanceForURL(const GURL& url);
+  content::SiteInstance* GetSiteInstanceForURL(const GURL& url);
 
   // Adds the given SiteInstance to our map, to ensure that we do not create
   // another SiteInstance for the same site.
-  void RegisterSiteInstance(SiteInstance* site_instance);
+  void RegisterSiteInstance(content::SiteInstance* site_instance);
 
   // Removes the given SiteInstance from our map, after all references to it
   // have been deleted.  This means it is safe to create a new SiteInstance
   // if the user later visits a page from this site, within this
   // BrowsingInstance.
-  void UnregisterSiteInstance(SiteInstance* site_instance);
+  void UnregisterSiteInstance(content::SiteInstance* site_instance);
 
-  friend class SiteInstance;
+  friend class SiteInstanceImpl;
+  friend class content::SiteInstance;
 
   friend class base::RefCounted<BrowsingInstance>;
 
@@ -101,7 +103,7 @@ class CONTENT_EXPORT BrowsingInstance
 
  private:
   // Map of site to SiteInstance, to ensure we only have one SiteInstance per
-  typedef base::hash_map<std::string, SiteInstance*> SiteInstanceMap;
+  typedef base::hash_map<std::string, content::SiteInstance*> SiteInstanceMap;
 
   // Map of BrowserContext to SiteInstanceMap, for use in the process-per-site
   // model.
@@ -120,7 +122,7 @@ class CONTENT_EXPORT BrowsingInstance
   // Utility routine which removes the passed SiteInstance from the passed
   // SiteInstanceMap.
   bool RemoveSiteInstanceFromMap(SiteInstanceMap* map, const std::string& site,
-                                 SiteInstance* site_instance);
+                                 content::SiteInstance* site_instance);
 
   // Common browser context to which all SiteInstances in this BrowsingInstance
   // must belong.
@@ -128,7 +130,7 @@ class CONTENT_EXPORT BrowsingInstance
 
   // Map of site to SiteInstance, to ensure we only have one SiteInstance per
   // site.  The site string should be the possibly_invalid_spec() of a GURL
-  // obtained with SiteInstance::GetSiteForURL.  Note that this map may not
+  // obtained with SiteInstanceImpl::GetSiteForURL.  Note that this map may not
   // contain every active SiteInstance, because a race exists where two
   // SiteInstances can be assigned to the same site.  This is ok in rare cases.
   // This field is only used if we are not using process-per-site.
diff --git a/content/browser/child_process_security_policy.cc b/content/browser/child_process_security_policy.cc
index eeeac3f..4a305b1 100644
--- a/content/browser/child_process_security_policy.cc
+++ b/content/browser/child_process_security_policy.cc
@@ -10,13 +10,15 @@
 #include "base/platform_file.h"
 #include "base/stl_util.h"
 #include "base/string_util.h"
+#include "content/browser/site_instance_impl.h"
 #include "content/public/browser/content_browser_client.h"
-#include "content/browser/site_instance.h"
 #include "content/public/common/bindings_policy.h"
 #include "content/public/common/url_constants.h"
 #include "googleurl/src/gurl.h"
 #include "net/url_request/url_request.h"
 
+using content::SiteInstance;
+
 static const int kReadFilePermissions =
     base::PLATFORM_FILE_OPEN |
     base::PLATFORM_FILE_READ |
@@ -103,7 +105,7 @@ class ChildProcessSecurityPolicy::SecurityState {
   bool CanUseCookiesForOrigin(const GURL& gurl) {
     if (origin_lock_.is_empty())
       return true;
-    GURL site_gurl = SiteInstance::GetSiteForURL(NULL, gurl);
+    GURL site_gurl = SiteInstanceImpl::GetSiteForURL(NULL, gurl);
     return origin_lock_ == site_gurl;
   }
 
@@ -478,7 +480,7 @@ bool ChildProcessSecurityPolicy::CanUseCookiesForOrigin(int child_id,
 
 void ChildProcessSecurityPolicy::LockToOrigin(int child_id, const GURL& gurl) {
   // "gurl" can be currently empty in some cases, such as file://blah.
-  DCHECK(SiteInstance::GetSiteForURL(NULL, gurl) == gurl);
+  DCHECK(SiteInstanceImpl::GetSiteForURL(NULL, gurl) == gurl);
   base::AutoLock lock(lock_);
   SecurityStateMap::iterator state = security_state_.find(child_id);
   DCHECK(state != security_state_.end());
diff --git a/content/browser/debugger/render_view_devtools_agent_host.cc b/content/browser/debugger/render_view_devtools_agent_host.cc
index 7aad562..943930f 100644
--- a/content/browser/debugger/render_view_devtools_agent_host.cc
+++ b/content/browser/debugger/render_view_devtools_agent_host.cc
@@ -10,7 +10,7 @@
 #include "content/browser/debugger/render_view_devtools_agent_host.h"
 #include "content/browser/renderer_host/render_process_host_impl.h"
 #include "content/browser/renderer_host/render_view_host.h"
-#include "content/browser/site_instance.h"
+#include "content/browser/site_instance_impl.h"
 #include "content/browser/tab_contents/tab_contents.h"
 #include "content/common/devtools_messages.h"
 #include "content/public/browser/content_browser_client.h"
diff --git a/content/browser/renderer_host/render_view_host.cc b/content/browser/renderer_host/render_view_host.cc
index 921bd94f..47a2b63 100644
--- a/content/browser/renderer_host/render_view_host.cc
+++ b/content/browser/renderer_host/render_view_host.cc
@@ -26,7 +26,6 @@
 #include "content/browser/renderer_host/render_process_host_impl.h"
 #include "content/browser/renderer_host/render_widget_host.h"
 #include "content/browser/renderer_host/render_widget_host_view.h"
-#include "content/browser/site_instance.h"
 #include "content/common/desktop_notification_messages.h"
 #include "content/common/drag_messages.h"
 #include "content/common/speech_input_messages.h"
@@ -58,6 +57,7 @@ using base::TimeDelta;
 using content::BrowserMessageFilter;
 using content::BrowserThread;
 using content::RenderViewHostDelegate;
+using content::SiteInstance;
 using content::UserMetricsAction;
 using WebKit::WebConsoleMessage;
 using WebKit::WebDragOperation;
@@ -110,7 +110,7 @@ RenderViewHost::RenderViewHost(SiteInstance* instance,
                                int routing_id,
                                SessionStorageNamespace* session_storage)
     : RenderWidgetHost(instance->GetProcess(), routing_id),
-      instance_(instance),
+      instance_(static_cast<SiteInstanceImpl*>(instance)),
       delegate_(delegate),
       waiting_for_drag_context_response_(false),
       enabled_bindings_(0),
diff --git a/content/browser/renderer_host/render_view_host.h b/content/browser/renderer_host/render_view_host.h
index e766d24..aa12e85 100644
--- a/content/browser/renderer_host/render_view_host.h
+++ b/content/browser/renderer_host/render_view_host.h
@@ -16,6 +16,7 @@
 #include "base/process_util.h"
 #include "base/values.h"
 #include "content/browser/renderer_host/render_widget_host.h"
+#include "content/browser/site_instance_impl.h"
 #include "content/common/content_export.h"
 #include "content/public/browser/notification_observer.h"
 #include "content/public/common/stop_find_action.h"
@@ -34,7 +35,6 @@ class FilePath;
 class GURL;
 class PowerSaveBlocker;
 class SessionStorageNamespace;
-class SiteInstance;
 class SkBitmap;
 class ViewMsg_Navigate;
 struct ContextMenuParams;
@@ -139,13 +139,13 @@ class CONTENT_EXPORT RenderViewHost : public RenderWidgetHost {
   // tab contentses to share the same session storage (part of the WebStorage
   // spec) space. This is useful when restoring tabs, but most callers should
   // pass in NULL which will cause a new SessionStorageNamespace to be created.
-  RenderViewHost(SiteInstance* instance,
+  RenderViewHost(content::SiteInstance* instance,
                  content::RenderViewHostDelegate* delegate,
                  int routing_id,
                  SessionStorageNamespace* session_storage_namespace);
   virtual ~RenderViewHost();
 
-  SiteInstance* site_instance() const { return instance_; }
+  content::SiteInstance* site_instance() const { return instance_; }
   content::RenderViewHostDelegate* delegate() const { return delegate_; }
   void set_delegate(content::RenderViewHostDelegate* d) {
     CHECK(d);  // http://crbug.com/82827
@@ -612,7 +612,7 @@ class CONTENT_EXPORT RenderViewHost : public RenderWidgetHost {
   // The SiteInstance associated with this RenderViewHost.  All pages drawn
   // in this RenderViewHost are part of this SiteInstance.  Should not change
   // over time.
-  scoped_refptr<SiteInstance> instance_;
+  scoped_refptr<SiteInstanceImpl> instance_;
 
   // Our delegate, which wants to know about changes in the RenderView.
   content::RenderViewHostDelegate* delegate_;
diff --git a/content/browser/renderer_host/render_view_host_factory.cc b/content/browser/renderer_host/render_view_host_factory.cc
index 3e7fe70..f54ac09 100644
--- a/content/browser/renderer_host/render_view_host_factory.cc
+++ b/content/browser/renderer_host/render_view_host_factory.cc
@@ -7,6 +7,8 @@
 #include "base/logging.h"
 #include "content/browser/renderer_host/render_view_host.h"
 
+using content::SiteInstance;
+
 // static
 RenderViewHostFactory* RenderViewHostFactory::factory_ = NULL;
 
diff --git a/content/browser/renderer_host/render_view_host_factory.h b/content/browser/renderer_host/render_view_host_factory.h
index f63a1e7..96a64df 100644
--- a/content/browser/renderer_host/render_view_host_factory.h
+++ b/content/browser/renderer_host/render_view_host_factory.h
@@ -11,10 +11,10 @@
 
 class RenderViewHost;
 class SessionStorageNamespace;
-class SiteInstance;
 
 namespace content {
 class RenderViewHostDelegate;
+class SiteInstance;
 }
 
 // A factory for creating RenderViewHosts. There is a global factory function
@@ -25,7 +25,7 @@ class RenderViewHostFactory {
   // Creates a RenderViewHost using the currently registered factory, or the
   // default one if no factory is registered. Ownership of the returned
   // pointer will be passed to the caller.
-  static RenderViewHost* Create(SiteInstance* instance,
+  static RenderViewHost* Create(content::SiteInstance* instance,
                                 content::RenderViewHostDelegate* delegate,
                                 int routing_id,
                                 SessionStorageNamespace* session_storage);
@@ -42,7 +42,7 @@ class RenderViewHostFactory {
   // You can derive from this class and specify an implementation for this
   // function to create a different kind of RenderViewHost for testing.
   virtual RenderViewHost* CreateRenderViewHost(
-      SiteInstance* instance,
+      content::SiteInstance* instance,
       content::RenderViewHostDelegate* delegate,
       int routing_id,
       SessionStorageNamespace* session_storage_namespace) = 0;
diff --git a/content/browser/renderer_host/render_view_host_manager_browsertest.cc b/content/browser/renderer_host/render_view_host_manager_browsertest.cc
index 5565ece..2d05866 100644
--- a/content/browser/renderer_host/render_view_host_manager_browsertest.cc
+++ b/content/browser/renderer_host/render_view_host_manager_browsertest.cc
@@ -9,7 +9,7 @@
 #include "chrome/test/base/in_process_browser_test.h"
 #include "chrome/test/base/ui_test_utils.h"
 #include "content/browser/renderer_host/render_view_host.h"
-#include "content/browser/site_instance.h"
+#include "content/browser/site_instance_impl.h"
 #include "content/browser/tab_contents/tab_contents.h"
 #include "content/public/browser/notification_details.h"
 #include "content/public/browser/notification_observer.h"
@@ -20,6 +20,8 @@
 #include "net/base/net_util.h"
 #include "net/test/test_server.h"
 
+using content::SiteInstance;
+
 class RenderViewHostManagerTest : public InProcessBrowserTest {
  public:
   RenderViewHostManagerTest() {
diff --git a/content/browser/renderer_host/test_render_view_host.cc b/content/browser/renderer_host/test_render_view_host.cc
index 3237881..764ee86 100644
--- a/content/browser/renderer_host/test_render_view_host.cc
+++ b/content/browser/renderer_host/test_render_view_host.cc
@@ -6,7 +6,7 @@
 #include "content/browser/browser_url_handler.h"
 #include "content/browser/renderer_host/test_backing_store.h"
 #include "content/browser/renderer_host/test_render_view_host.h"
-#include "content/browser/site_instance.h"
+#include "content/browser/site_instance_impl.h"
 #include "content/browser/tab_contents/navigation_controller_impl.h"
 #include "content/browser/tab_contents/navigation_entry_impl.h"
 #include "content/browser/tab_contents/test_tab_contents.h"
@@ -23,6 +23,7 @@
 using content::NavigationController;
 using content::NavigationEntry;
 using content::RenderViewHostDelegate;
+using content::SiteInstance;
 using webkit::forms::PasswordForm;
 
 void InitNavigateParams(ViewHostMsg_FrameNavigate_Params* params,
@@ -312,7 +313,8 @@ RenderViewHost* TestRenderViewHostFactory::CreateRenderViewHost(
     int routing_id,
     SessionStorageNamespace* session_storage) {
   // See declaration of render_process_host_factory_ below.
-  instance->set_render_process_host_factory(render_process_host_factory_);
+  static_cast<SiteInstanceImpl*>(instance)->
+      set_render_process_host_factory(render_process_host_factory_);
   return new TestRenderViewHost(instance, delegate, routing_id);
 }
 
@@ -370,8 +372,7 @@ TestTabContents* RenderViewHostTestHarness::CreateTestTabContents() {
     browser_context_.reset(new TestBrowserContext());
 
   // This will be deleted when the TabContents goes away.
-  SiteInstance* instance =
-      SiteInstance::CreateSiteInstance(browser_context_.get());
+  SiteInstance* instance = SiteInstance::Create(browser_context_.get());
 
   return new TestTabContents(browser_context_.get(), instance);
 }
diff --git a/content/browser/renderer_host/test_render_view_host.h b/content/browser/renderer_host/test_render_view_host.h
index 3afffc5..783536b 100644
--- a/content/browser/renderer_host/test_render_view_host.h
+++ b/content/browser/renderer_host/test_render_view_host.h
@@ -21,13 +21,13 @@ namespace content {
 class BrowserContext;
 class NavigationController;
 class RenderProcessHostFactory;
+class SiteInstance;
 }
 
 namespace gfx {
 class Rect;
 }
 
-class SiteInstance;
 class TestTabContents;
 struct ViewHostMsg_FrameNavigate_Params;
 
@@ -175,7 +175,7 @@ class TestRenderViewHost : public RenderViewHost {
   static TestRenderViewHost* GetPendingForController(
       content::NavigationController* controller);
 
-  TestRenderViewHost(SiteInstance* instance,
+  TestRenderViewHost(content::SiteInstance* instance,
                      content::RenderViewHostDelegate* delegate,
                      int routing_id);
   virtual ~TestRenderViewHost();
@@ -276,7 +276,7 @@ class TestRenderViewHostFactory : public RenderViewHostFactory {
   virtual void set_render_process_host_factory(
       content::RenderProcessHostFactory* rph_factory);
   virtual RenderViewHost* CreateRenderViewHost(
-      SiteInstance* instance,
+      content::SiteInstance* instance,
       content::RenderViewHostDelegate* delegate,
       int routing_id,
       SessionStorageNamespace* session_storage) OVERRIDE;
diff --git a/content/browser/site_instance.cc b/content/browser/site_instance_impl.cc
index 9fecc16..feb5402 100644
--- a/content/browser/site_instance.cc
+++ b/content/browser/site_instance_impl.cc
@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-#include "content/browser/site_instance.h"
+#include "content/browser/site_instance_impl.h"
 
 #include "base/command_line.h"
 #include "content/browser/browsing_instance.h"
@@ -16,6 +16,8 @@
 #include "content/public/common/url_constants.h"
 #include "net/base/registry_controlled_domain.h"
 
+using content::SiteInstance;
+
 static bool IsURLSameAsAnySiteInstance(const GURL& url) {
   if (!url.is_valid())
     return false;
@@ -29,9 +31,9 @@ static bool IsURLSameAsAnySiteInstance(const GURL& url) {
       content::GetContentClient()->browser()->IsURLSameAsAnySiteInstance(url);
 }
 
-int32 SiteInstance::next_site_instance_id_ = 1;
+int32 SiteInstanceImpl::next_site_instance_id_ = 1;
 
-SiteInstance::SiteInstance(BrowsingInstance* browsing_instance)
+SiteInstanceImpl::SiteInstanceImpl(BrowsingInstance* browsing_instance)
     : id_(next_site_instance_id_++),
       browsing_instance_(browsing_instance),
       render_process_host_factory_(NULL),
@@ -43,21 +45,26 @@ SiteInstance::SiteInstance(BrowsingInstance* browsing_instance)
                  content::NotificationService::AllBrowserContextsAndSources());
 }
 
-SiteInstance::~SiteInstance() {
+SiteInstanceImpl::~SiteInstanceImpl() {
   content::GetContentClient()->browser()->SiteInstanceDeleting(this);
 
   // Now that no one is referencing us, we can safely remove ourselves from
   // the BrowsingInstance.  Any future visits to a page from this site
   // (within the same BrowsingInstance) can safely create a new SiteInstance.
   if (has_site_)
-    browsing_instance_->UnregisterSiteInstance(this);
+    browsing_instance_->UnregisterSiteInstance(
+        static_cast<SiteInstance*>(this));
+}
+
+int32 SiteInstanceImpl::GetId() {
+  return id_;
 }
 
-bool SiteInstance::HasProcess() const {
+bool SiteInstanceImpl::HasProcess() const {
   return (process_ != NULL);
 }
 
-content::RenderProcessHost* SiteInstance::GetProcess() {
+content::RenderProcessHost* SiteInstanceImpl::GetProcess() {
   // TODO(erikkay) It would be nice to ensure that the renderer type had been
   // properly set before we get here.  The default tab creation case winds up
   // with no site set at this point, so it will default to TYPE_NORMAL.  This
@@ -93,7 +100,7 @@ content::RenderProcessHost* SiteInstance::GetProcess() {
   return process_;
 }
 
-void SiteInstance::SetSite(const GURL& url) {
+void SiteInstanceImpl::SetSite(const GURL& url) {
   // A SiteInstance's site should not change.
   // TODO(creis): When following links or script navigations, we can currently
   // render pages from other sites in this SiteInstance.  This will eventually
@@ -116,15 +123,23 @@ void SiteInstance::SetSite(const GURL& url) {
     LockToOrigin();
 }
 
-bool SiteInstance::HasRelatedSiteInstance(const GURL& url) {
+const GURL& SiteInstanceImpl::GetSite() const {
+  return site_;
+}
+
+bool SiteInstanceImpl::HasSite() const {
+  return has_site_;
+}
+
+bool SiteInstanceImpl::HasRelatedSiteInstance(const GURL& url) {
   return browsing_instance_->HasSiteInstance(url);
 }
 
-SiteInstance* SiteInstance::GetRelatedSiteInstance(const GURL& url) {
+SiteInstance* SiteInstanceImpl::GetRelatedSiteInstance(const GURL& url) {
   return browsing_instance_->GetSiteInstanceForURL(url);
 }
 
-bool SiteInstance::HasWrongProcessForURL(const GURL& url) const {
+bool SiteInstanceImpl::HasWrongProcessForURL(const GURL& url) const {
   // Having no process isn't a problem, since we'll assign it correctly.
   if (!HasProcess())
     return false;
@@ -141,18 +156,17 @@ bool SiteInstance::HasWrongProcessForURL(const GURL& url) const {
       process_, browsing_instance_->browser_context(), site_url);
 }
 
-content::BrowserContext* SiteInstance::GetBrowserContext() const {
+content::BrowserContext* SiteInstanceImpl::GetBrowserContext() const {
   return browsing_instance_->browser_context();
 }
 
 /*static*/
-SiteInstance* SiteInstance::CreateSiteInstance(
-    content::BrowserContext* browser_context) {
-  return new SiteInstance(new BrowsingInstance(browser_context));
+SiteInstance* SiteInstance::Create(content::BrowserContext* browser_context) {
+  return new SiteInstanceImpl(new BrowsingInstance(browser_context));
 }
 
 /*static*/
-SiteInstance* SiteInstance::CreateSiteInstanceForURL(
+SiteInstance* SiteInstance::CreateForURL(
     content::BrowserContext* browser_context, const GURL& url) {
   // This BrowsingInstance may be deleted if it returns an existing
   // SiteInstance.
@@ -162,9 +176,9 @@ SiteInstance* SiteInstance::CreateSiteInstanceForURL(
 }
 
 /*static*/
-GURL SiteInstance::GetSiteForURL(content::BrowserContext* browser_context,
-                                 const GURL& real_url) {
-  GURL url = GetEffectiveURL(browser_context, real_url);
+GURL SiteInstanceImpl::GetSiteForURL(content::BrowserContext* browser_context,
+                                     const GURL& real_url) {
+  GURL url = SiteInstanceImpl::GetEffectiveURL(browser_context, real_url);
 
   // URLs with no host should have an empty site.
   GURL site;
@@ -199,9 +213,10 @@ GURL SiteInstance::GetSiteForURL(content::BrowserContext* browser_context,
 
 /*static*/
 bool SiteInstance::IsSameWebSite(content::BrowserContext* browser_context,
-                                 const GURL& real_url1, const GURL& real_url2) {
-  GURL url1 = GetEffectiveURL(browser_context, real_url1);
-  GURL url2 = GetEffectiveURL(browser_context, real_url2);
+                                 const GURL& real_url1,
+                                 const GURL& real_url2) {
+  GURL url1 = SiteInstanceImpl::GetEffectiveURL(browser_context, real_url1);
+  GURL url2 = SiteInstanceImpl::GetEffectiveURL(browser_context, real_url2);
 
   // We infer web site boundaries based on the registered domain name of the
   // top-level page and the scheme.  We do not pay attention to the port if
@@ -226,15 +241,16 @@ bool SiteInstance::IsSameWebSite(content::BrowserContext* browser_context,
 }
 
 /*static*/
-GURL SiteInstance::GetEffectiveURL(content::BrowserContext* browser_context,
-                                   const GURL& url) {
+GURL SiteInstanceImpl::GetEffectiveURL(
+    content::BrowserContext* browser_context,
+    const GURL& url) {
   return content::GetContentClient()->browser()->
       GetEffectiveURL(browser_context, url);
 }
 
-void SiteInstance::Observe(int type,
-                           const content::NotificationSource& source,
-                           const content::NotificationDetails& details) {
+void SiteInstanceImpl::Observe(int type,
+                               const content::NotificationSource& source,
+                               const content::NotificationDetails& details) {
   DCHECK(type == content::NOTIFICATION_RENDERER_PROCESS_TERMINATED);
   content::RenderProcessHost* rph =
       content::Source<content::RenderProcessHost>(source).ptr();
@@ -242,7 +258,7 @@ void SiteInstance::Observe(int type,
     process_ = NULL;
 }
 
-void SiteInstance::LockToOrigin() {
+void SiteInstanceImpl::LockToOrigin() {
   const CommandLine& command_line = *CommandLine::ForCurrentProcess();
   if (command_line.HasSwitch(switches::kEnableStrictSiteIsolation)) {
     ChildProcessSecurityPolicy* policy =
diff --git a/content/browser/site_instance_impl.h b/content/browser/site_instance_impl.h
new file mode 100644
index 0000000..bee9383
--- /dev/null
+++ b/content/browser/site_instance_impl.h
@@ -0,0 +1,119 @@
+// Copyright (c) 2012 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef CONTENT_BROWSER_SITE_INSTANCE_IMPL_H_
+#define CONTENT_BROWSER_SITE_INSTANCE_IMPL_H_
+#pragma once
+
+#include "content/browser/renderer_host/render_process_host_impl.h"
+#include "content/common/content_export.h"
+#include "content/public/browser/notification_observer.h"
+#include "content/public/browser/notification_registrar.h"
+#include "content/public/browser/site_instance.h"
+#include "googleurl/src/gurl.h"
+
+namespace content {
+class RenderProcessHostFactory;
+}
+
+class CONTENT_EXPORT SiteInstanceImpl : public content::SiteInstance,
+                                        public content::NotificationObserver {
+ public:
+  // content::SiteInstance interface overrides.
+  virtual int32 GetId() OVERRIDE;
+  virtual bool HasProcess() const OVERRIDE;
+  virtual  content::RenderProcessHost* GetProcess() OVERRIDE;
+  virtual const GURL& GetSite() const OVERRIDE;
+  virtual SiteInstance* GetRelatedSiteInstance(const GURL& url) OVERRIDE;
+  virtual content::BrowserContext* GetBrowserContext() const OVERRIDE;
+
+  // Set the web site that this SiteInstance is rendering pages for.
+  // This includes the scheme and registered domain, but not the port.  If the
+  // URL does not have a valid registered domain, then the full hostname is
+  // stored.
+  void SetSite(const GURL& url);
+  bool HasSite() const;
+
+  // Returns whether there is currently a related SiteInstance (registered with
+  // BrowsingInstance) for the site of the given url.  If so, we should try to
+  // avoid dedicating an unused SiteInstance to it (e.g., in a new tab).
+  bool HasRelatedSiteInstance(const GURL& url);
+
+  // Returns whether this SiteInstance has a process that is the wrong type for
+  // the given URL.  If so, the browser should force a process swap when
+  // navigating to the URL.
+  bool HasWrongProcessForURL(const GURL& url) const;
+
+  // Sets the factory used to create new RenderProcessHosts. This will also be
+  // passed on to SiteInstances spawned by this one.
+  // The factory must outlive the SiteInstance; ownership is not transferred. It
+  // may be NULL, in which case the default BrowserRenderProcessHost will be
+  // created (this is the behavior if you don't call this function).
+  void set_render_process_host_factory(
+      content::RenderProcessHostFactory* rph_factory) {
+    render_process_host_factory_ = rph_factory;
+  }
+
+  // Returns the site for the given URL, which includes only the scheme and
+  // registered domain.  Returns an empty GURL if the URL has no host.
+  static GURL GetSiteForURL(content::BrowserContext* context, const GURL& url);
+
+ protected:
+  friend class BrowsingInstance;
+  friend class content::SiteInstance;
+
+  // Virtual to allow tests to extend it.
+  virtual ~SiteInstanceImpl();
+
+  // Create a new SiteInstance.  Protected to give access to BrowsingInstance
+  // and tests; most callers should use Create or GetRelatedSiteInstance
+  // instead.
+  explicit SiteInstanceImpl(BrowsingInstance* browsing_instance);
+
+ private:
+  // Get the effective URL for the given actual URL.
+  static GURL GetEffectiveURL(content::BrowserContext* browser_context,
+                              const GURL& url);
+
+  // content::NotificationObserver implementation.
+  virtual void Observe(int type,
+                       const content::NotificationSource& source,
+                       const content::NotificationDetails& details) OVERRIDE;
+
+  // Used to restrict a process' origin access rights.
+  void LockToOrigin();
+
+  // The next available SiteInstance ID.
+  static int32 next_site_instance_id_;
+
+  // A unique ID for this SiteInstance.
+  int32 id_;
+
+  content::NotificationRegistrar registrar_;
+
+  // BrowsingInstance to which this SiteInstance belongs.
+  scoped_refptr<BrowsingInstance> browsing_instance_;
+
+  // Factory for new RenderProcessHosts, not owned by this class. NULL indiactes
+  // that the default BrowserRenderProcessHost should be created.
+  const content::RenderProcessHostFactory* render_process_host_factory_;
+
+  // Current RenderProcessHost that is rendering pages for this SiteInstance.
+  // This pointer will only change once the RenderProcessHost is destructed.  It
+  // will still remain the same even if the process crashes, since in that
+  // scenario the RenderProcessHost remains the same.
+  content::RenderProcessHost* process_;
+
+  // The web site that this SiteInstance is rendering pages for.
+  GURL site_;
+
+  // Whether SetSite has been called.
+  bool has_site_;
+
+  FRIEND_TEST_ALL_PREFIXES(RenderViewHostManagerTest, NewTabPageProcesses);
+
+  DISALLOW_COPY_AND_ASSIGN(SiteInstanceImpl);
+};
+
+#endif  // CONTENT_BROWSER_SITE_INSTANCE_IMPL_H_
diff --git a/content/browser/site_instance_unittest.cc b/content/browser/site_instance_impl_unittest.cc
index f436471..f45baf7 100644
--- a/content/browser/site_instance_unittest.cc
+++ b/content/browser/site_instance_impl_unittest.cc
@@ -12,7 +12,7 @@
 #include "content/browser/renderer_host/render_process_host_impl.h"
 #include "content/browser/renderer_host/render_view_host.h"
 #include "content/browser/renderer_host/test_render_view_host.h"
-#include "content/browser/site_instance.h"
+#include "content/browser/site_instance_impl.h"
 #include "content/browser/tab_contents/navigation_entry_impl.h"
 #include "content/browser/tab_contents/tab_contents.h"
 #include "content/browser/webui/empty_web_ui_factory.h"
@@ -27,6 +27,7 @@ using content::BrowserThread;
 using content::BrowserThreadImpl;
 using content::NavigationEntry;
 using content::NavigationEntryImpl;
+using content::SiteInstance;
 
 namespace {
 
@@ -152,7 +153,7 @@ class TestBrowsingInstance : public BrowsingInstance {
   int* delete_counter_;
 };
 
-class TestSiteInstance : public SiteInstance {
+class TestSiteInstance : public SiteInstanceImpl {
  public:
   static TestSiteInstance* CreateTestSiteInstance(
       content::BrowserContext* browser_context,
@@ -165,7 +166,7 @@ class TestSiteInstance : public SiteInstance {
 
  private:
   TestSiteInstance(BrowsingInstance* browsing_instance, int* delete_counter)
-    : SiteInstance(browsing_instance), delete_counter_(delete_counter) {}
+    : SiteInstanceImpl(browsing_instance), delete_counter_(delete_counter) {}
   virtual ~TestSiteInstance() {
     (*delete_counter_)++;
   }
@@ -248,10 +249,10 @@ TEST_F(SiteInstanceTest, CloneNavigationEntry) {
   int browsing_delete_counter = 0;
   const GURL url("test:foo");
 
-  SiteInstance* instance1 =
+  SiteInstanceImpl* instance1 =
       TestSiteInstance::CreateTestSiteInstance(NULL, &site_delete_counter1,
                                                &browsing_delete_counter);
-  SiteInstance* instance2 =
+  SiteInstanceImpl* instance2 =
       TestSiteInstance::CreateTestSiteInstance(NULL, &site_delete_counter2,
                                                &browsing_delete_counter);
 
@@ -284,14 +285,14 @@ TEST_F(SiteInstanceTest, GetProcess) {
   // Ensure that GetProcess returns a process.
   scoped_ptr<TestBrowserContext> browser_context(new TestBrowserContext());
   scoped_ptr<content::RenderProcessHost> host1;
-  scoped_refptr<SiteInstance> instance(
-      SiteInstance::CreateSiteInstance(browser_context.get()));
+  scoped_refptr<SiteInstanceImpl> instance(static_cast<SiteInstanceImpl*>(
+      SiteInstance::Create(browser_context.get())));
   host1.reset(instance->GetProcess());
   EXPECT_TRUE(host1.get() != NULL);
 
   // Ensure that GetProcess creates a new process.
-  scoped_refptr<SiteInstance> instance2(
-      SiteInstance::CreateSiteInstance(browser_context.get()));
+  scoped_refptr<SiteInstanceImpl> instance2(static_cast<SiteInstanceImpl*>(
+      SiteInstance::Create(browser_context.get())));
   scoped_ptr<content::RenderProcessHost> host2(instance2->GetProcess());
   EXPECT_TRUE(host2.get() != NULL);
   EXPECT_NE(host1.get(), host2.get());
@@ -299,14 +300,15 @@ TEST_F(SiteInstanceTest, GetProcess) {
 
 // Test to ensure SetSite and site() work properly.
 TEST_F(SiteInstanceTest, SetSite) {
-  scoped_refptr<SiteInstance> instance(SiteInstance::CreateSiteInstance(NULL));
-  EXPECT_FALSE(instance->has_site());
-  EXPECT_TRUE(instance->site().is_empty());
+  scoped_refptr<SiteInstanceImpl> instance(static_cast<SiteInstanceImpl*>(
+      SiteInstance::Create(NULL)));
+  EXPECT_FALSE(instance->HasSite());
+  EXPECT_TRUE(instance->GetSite().is_empty());
 
   instance->SetSite(GURL("http://www.google.com/index.html"));
-  EXPECT_EQ(GURL("http://google.com"), instance->site());
+  EXPECT_EQ(GURL("http://google.com"), instance->GetSite());
 
-  EXPECT_TRUE(instance->has_site());
+  EXPECT_TRUE(instance->HasSite());
 }
 
 // Test to ensure GetSiteForURL properly returns sites for URLs.
@@ -314,28 +316,29 @@ TEST_F(SiteInstanceTest, GetSiteForURL) {
   // Pages are irrelevant.
   GURL test_url = GURL("http://www.google.com/index.html");
   EXPECT_EQ(GURL("http://google.com"),
-            SiteInstance::GetSiteForURL(NULL, test_url));
+            SiteInstanceImpl::GetSiteForURL(NULL, test_url));
 
   // Ports are irrlevant.
   test_url = GURL("https://www.google.com:8080");
   EXPECT_EQ(GURL("https://google.com"),
-            SiteInstance::GetSiteForURL(NULL, test_url));
+            SiteInstanceImpl::GetSiteForURL(NULL, test_url));
 
   // Javascript URLs have no site.
   test_url = GURL("javascript:foo();");
-  EXPECT_EQ(GURL(), SiteInstance::GetSiteForURL(NULL, test_url));
+  EXPECT_EQ(GURL(), SiteInstanceImpl::GetSiteForURL(NULL, test_url));
 
   test_url = GURL("http://foo/a.html");
-  EXPECT_EQ(GURL("http://foo"), SiteInstance::GetSiteForURL(NULL, test_url));
+  EXPECT_EQ(GURL("http://foo"), SiteInstanceImpl::GetSiteForURL(
+      NULL, test_url));
 
   test_url = GURL("file:///C:/Downloads/");
-  EXPECT_EQ(GURL(), SiteInstance::GetSiteForURL(NULL, test_url));
+  EXPECT_EQ(GURL(), SiteInstanceImpl::GetSiteForURL(NULL, test_url));
 
   // TODO(creis): Do we want to special case file URLs to ensure they have
   // either no site or a special "file://" site?  We currently return
   // "file://home/" as the site, which seems broken.
   // test_url = GURL("file://home/");
-  // EXPECT_EQ(GURL(), SiteInstance::GetSiteForURL(NULL, test_url));
+  // EXPECT_EQ(GURL(), SiteInstanceImpl::GetSiteForURL(NULL, test_url));
 }
 
 // Test of distinguishing URLs from different sites.  Most of this logic is
@@ -368,8 +371,8 @@ TEST_F(SiteInstanceTest, IsSameWebSite) {
   // The URLs specified by the ContentBrowserClient should also be treated as
   // same site.
   EXPECT_TRUE(SiteInstance::IsSameWebSite(NULL, url_crash, url_foo));
-  EXPECT_TRUE(
-      SiteInstance::IsSameWebSite(NULL, url_browser_specified, url_foo));
+  EXPECT_TRUE(SiteInstance::IsSameWebSite(NULL, url_browser_specified,
+                                          url_foo));
 }
 
 // Test to ensure that there is only one SiteInstance per site in a given
@@ -381,14 +384,16 @@ TEST_F(SiteInstanceTest, OneSiteInstancePerSite) {
   browsing_instance->set_use_process_per_site(false);
 
   const GURL url_a1("http://www.google.com/1.html");
-  scoped_refptr<SiteInstance> site_instance_a1(
-      browsing_instance->GetSiteInstanceForURL(url_a1));
+  scoped_refptr<SiteInstanceImpl> site_instance_a1(
+      static_cast<SiteInstanceImpl*>(
+          browsing_instance->GetSiteInstanceForURL(url_a1)));
   EXPECT_TRUE(site_instance_a1.get() != NULL);
 
   // A separate site should create a separate SiteInstance.
   const GURL url_b1("http://www.yahoo.com/");
-  scoped_refptr<SiteInstance> site_instance_b1(
-      browsing_instance->GetSiteInstanceForURL(url_b1));
+  scoped_refptr<SiteInstanceImpl> site_instance_b1(
+      static_cast<SiteInstanceImpl*>(
+          browsing_instance->GetSiteInstanceForURL(url_b1)));
   EXPECT_NE(site_instance_a1.get(), site_instance_b1.get());
 
   // Getting the new SiteInstance from the BrowsingInstance and from another
@@ -409,8 +414,9 @@ TEST_F(SiteInstanceTest, OneSiteInstancePerSite) {
       new TestBrowsingInstance(NULL, &delete_counter);
   browsing_instance2->set_use_process_per_site(false);
   // Ensure the new SiteInstance is ref counted so that it gets deleted.
-  scoped_refptr<SiteInstance> site_instance_a2_2(
-      browsing_instance2->GetSiteInstanceForURL(url_a2));
+  scoped_refptr<SiteInstanceImpl> site_instance_a2_2(
+      static_cast<SiteInstanceImpl*>(
+          browsing_instance2->GetSiteInstanceForURL(url_a2)));
   EXPECT_NE(site_instance_a1.get(), site_instance_a2_2.get());
 
   // Should be able to see that we do have SiteInstances.
@@ -439,14 +445,16 @@ TEST_F(SiteInstanceTest, OneSiteInstancePerSiteInBrowserContext) {
   browsing_instance->set_use_process_per_site(true);
 
   const GURL url_a1("http://www.google.com/1.html");
-  scoped_refptr<SiteInstance> site_instance_a1(
-      browsing_instance->GetSiteInstanceForURL(url_a1));
+  scoped_refptr<SiteInstanceImpl> site_instance_a1(
+      static_cast<SiteInstanceImpl*>(
+          browsing_instance->GetSiteInstanceForURL(url_a1)));
   EXPECT_TRUE(site_instance_a1.get() != NULL);
 
   // A separate site should create a separate SiteInstance.
   const GURL url_b1("http://www.yahoo.com/");
-  scoped_refptr<SiteInstance> site_instance_b1(
-      browsing_instance->GetSiteInstanceForURL(url_b1));
+  scoped_refptr<SiteInstanceImpl> site_instance_b1(
+      static_cast<SiteInstanceImpl*>(
+          browsing_instance->GetSiteInstanceForURL(url_b1)));
   EXPECT_NE(site_instance_a1.get(), site_instance_b1.get());
 
   // Getting the new SiteInstance from the BrowsingInstance and from another
@@ -479,8 +487,9 @@ TEST_F(SiteInstanceTest, OneSiteInstancePerSiteInBrowserContext) {
       new TestBrowsingInstance(browser_context.get(), &delete_counter);
   browsing_instance3->set_use_process_per_site(true);
   // Ensure the new SiteInstance is ref counted so that it gets deleted.
-  scoped_refptr<SiteInstance> site_instance_a2_3(
-      browsing_instance3->GetSiteInstanceForURL(url_a2));
+  scoped_refptr<SiteInstanceImpl> site_instance_a2_3(
+      static_cast<SiteInstanceImpl*>(
+          browsing_instance3->GetSiteInstanceForURL(url_a2)));
   EXPECT_NE(site_instance_a1.get(), site_instance_a2_3.get());
 
   // Should be able to see that we do have SiteInstances.
@@ -502,9 +511,11 @@ TEST_F(SiteInstanceTest, OneSiteInstancePerSiteInBrowserContext) {
   // browsing_instances will be deleted when their SiteInstances are deleted
 }
 
-static SiteInstance* CreateSiteInstance(
+static SiteInstanceImpl* CreateSiteInstance(
     content::RenderProcessHostFactory* factory, const GURL& url) {
-  SiteInstance* instance = SiteInstance::CreateSiteInstanceForURL(NULL, url);
+  SiteInstanceImpl* instance =
+      reinterpret_cast<SiteInstanceImpl*>(
+          SiteInstance::CreateForURL(NULL, url));
   instance->set_render_process_host_factory(factory);
   return instance;
 }
@@ -522,14 +533,14 @@ TEST_F(SiteInstanceTest, ProcessSharingByType) {
     hosts.push_back(new MockRenderProcessHost(NULL));
 
   // Create some extension instances and make sure they share a process.
-  scoped_refptr<SiteInstance> extension1_instance(
+  scoped_refptr<SiteInstanceImpl> extension1_instance(
       CreateSiteInstance(&rph_factory,
-      GURL(kPrivilegedScheme + std::string("://foo/bar"))));
+          GURL(kPrivilegedScheme + std::string("://foo/bar"))));
   set_privileged_process_id(extension1_instance->GetProcess()->GetID());
 
-  scoped_refptr<SiteInstance> extension2_instance(
+  scoped_refptr<SiteInstanceImpl> extension2_instance(
       CreateSiteInstance(&rph_factory,
-      GURL(kPrivilegedScheme + std::string("://baz/bar"))));
+          GURL(kPrivilegedScheme + std::string("://baz/bar"))));
 
   scoped_ptr<content::RenderProcessHost> extension_host(
       extension1_instance->GetProcess());
@@ -537,11 +548,13 @@ TEST_F(SiteInstanceTest, ProcessSharingByType) {
             extension2_instance->GetProcess());
 
   // Create some WebUI instances and make sure they share a process.
-  scoped_refptr<SiteInstance> webui1_instance(CreateSiteInstance(&rph_factory,
+  scoped_refptr<SiteInstanceImpl> webui1_instance(CreateSiteInstance(
+      &rph_factory,
       GURL(chrome::kChromeUIScheme + std::string("://newtab"))));
   policy->GrantWebUIBindings(webui1_instance->GetProcess()->GetID());
 
-  scoped_refptr<SiteInstance> webui2_instance(CreateSiteInstance(&rph_factory,
+  scoped_refptr<SiteInstanceImpl> webui2_instance(CreateSiteInstance(
+      &rph_factory,
       GURL(chrome::kChromeUIScheme + std::string("://history"))));
 
   scoped_ptr<content::RenderProcessHost> dom_host(
@@ -564,14 +577,14 @@ TEST_F(SiteInstanceTest, ProcessSharingByType) {
 TEST_F(SiteInstanceTest, HasWrongProcessForURL) {
   scoped_ptr<TestBrowserContext> browser_context(new TestBrowserContext());
   scoped_ptr<content::RenderProcessHost> host;
-  scoped_refptr<SiteInstance> instance(
-      SiteInstance::CreateSiteInstance(browser_context.get()));
+  scoped_refptr<SiteInstanceImpl> instance(static_cast<SiteInstanceImpl*>(
+      SiteInstance::Create(browser_context.get())));
 
-  EXPECT_FALSE(instance->has_site());
-  EXPECT_TRUE(instance->site().is_empty());
+  EXPECT_FALSE(instance->HasSite());
+  EXPECT_TRUE(instance->GetSite().is_empty());
 
   instance->SetSite(GURL("http://evernote.com/"));
-  EXPECT_TRUE(instance->has_site());
+  EXPECT_TRUE(instance->HasSite());
 
   // Check prior to "assigning" a process to the instance, which is expected
   // to return false due to not being attached to any process yet.
diff --git a/content/browser/ssl/ssl_policy.cc b/content/browser/ssl/ssl_policy.cc
index 4b22e683..8bdcb10 100644
--- a/content/browser/ssl/ssl_policy.cc
+++ b/content/browser/ssl/ssl_policy.cc
@@ -12,7 +12,7 @@
 #include "base/string_util.h"
 #include "content/browser/renderer_host/render_process_host_impl.h"
 #include "content/browser/renderer_host/render_view_host.h"
-#include "content/browser/site_instance.h"
+#include "content/browser/site_instance_impl.h"
 #include "content/browser/ssl/ssl_cert_error_handler.h"
 #include "content/browser/ssl/ssl_request_info.h"
 #include "content/browser/tab_contents/navigation_entry_impl.h"
@@ -25,6 +25,7 @@
 #include "webkit/glue/resource_type.h"
 
 using content::NavigationEntryImpl;
+using content::SiteInstance;
 using content::SSLStatus;
 
 namespace {
diff --git a/content/browser/tab_contents/interstitial_page.cc b/content/browser/tab_contents/interstitial_page.cc
index 8f67b82..19f1643 100644
--- a/content/browser/tab_contents/interstitial_page.cc
+++ b/content/browser/tab_contents/interstitial_page.cc
@@ -16,7 +16,7 @@
 #include "content/browser/renderer_host/render_view_host.h"
 #include "content/browser/renderer_host/render_widget_host_view.h"
 #include "content/browser/renderer_host/resource_dispatcher_host.h"
-#include "content/browser/site_instance.h"
+#include "content/browser/site_instance_impl.h"
 #include "content/browser/tab_contents/navigation_controller_impl.h"
 #include "content/browser/tab_contents/navigation_entry_impl.h"
 #include "content/browser/tab_contents/tab_contents.h"
@@ -39,6 +39,7 @@ using content::NavigationController;
 using content::NavigationEntry;
 using content::NavigationEntryImpl;
 using content::RenderViewHostDelegate;
+using content::SiteInstance;
 using content::WebContents;
 using content::WebContentsView;
 using WebKit::WebDragOperation;
@@ -429,7 +430,7 @@ WebContents* InterstitialPage::tab() const {
 
 RenderViewHost* InterstitialPage::CreateRenderViewHost() {
   RenderViewHost* render_view_host = new RenderViewHost(
-      SiteInstance::CreateSiteInstance(tab()->GetBrowserContext()),
+      SiteInstance::Create(tab()->GetBrowserContext()),
       this, MSG_ROUTING_NONE, kInvalidSessionStorageNamespaceId);
   return render_view_host;
 }
diff --git a/content/browser/tab_contents/navigation_controller_impl.cc b/content/browser/tab_contents/navigation_controller_impl.cc
index 3c5ddee..05dbda2 100644
--- a/content/browser/tab_contents/navigation_controller_impl.cc
+++ b/content/browser/tab_contents/navigation_controller_impl.cc
@@ -14,7 +14,7 @@
 #include "content/browser/child_process_security_policy.h"
 #include "content/browser/in_process_webkit/session_storage_namespace.h"
 #include "content/browser/renderer_host/render_view_host.h"  // Temporary
-#include "content/browser/site_instance.h"
+#include "content/browser/site_instance_impl.h"
 #include "content/browser/tab_contents/interstitial_page.h"
 #include "content/browser/tab_contents/navigation_entry_impl.h"
 #include "content/browser/tab_contents/tab_contents.h"
@@ -37,6 +37,7 @@ using content::GlobalRequestID;
 using content::NavigationController;
 using content::NavigationEntry;
 using content::NavigationEntryImpl;
+using content::SiteInstance;
 using content::UserMetricsAction;
 using content::WebContents;
 
@@ -291,7 +292,7 @@ bool NavigationControllerImpl::IsInitialNavigation() {
 }
 
 NavigationEntryImpl* NavigationControllerImpl::GetEntryWithPageID(
-    SiteInstance* instance, int32 page_id) const {
+  SiteInstance* instance, int32 page_id) const {
   int index = GetEntryIndexWithPageID(instance, page_id);
   return (index != -1) ? entries_[index].get() : NULL;
 }
@@ -724,7 +725,7 @@ content::NavigationType NavigationControllerImpl::ClassifyNavigation(
       temp.append(base::IntToString(entries_[i]->GetPageID()));
       temp.append("_");
       if (entries_[i]->site_instance())
-        temp.append(base::IntToString(entries_[i]->site_instance()->id()));
+        temp.append(base::IntToString(entries_[i]->site_instance()->GetId()));
       else
         temp.append("N");
       if (entries_[i]->site_instance() != tab_contents_->GetSiteInstance())
@@ -813,7 +814,8 @@ void NavigationControllerImpl::RendererDidNavigateToNewPage(
   new_entry->SetReferrer(params.referrer);
   new_entry->SetPageID(params.page_id);
   new_entry->SetTransitionType(params.transition);
-  new_entry->set_site_instance(tab_contents_->GetSiteInstance());
+  new_entry->set_site_instance(
+      static_cast<SiteInstanceImpl*>(tab_contents_->GetSiteInstance()));
   new_entry->SetHasPostData(params.is_post);
 
   InsertOrReplaceEntry(new_entry, *did_replace_entry);
@@ -841,7 +843,8 @@ void NavigationControllerImpl::RendererDidNavigateToExistingPage(
     UpdateVirtualURLToURL(entry, params.url);
   DCHECK(entry->site_instance() == NULL ||
          entry->site_instance() == tab_contents_->GetSiteInstance());
-  entry->set_site_instance(tab_contents_->GetSiteInstance());
+  entry->set_site_instance(
+      static_cast<SiteInstanceImpl*>(tab_contents_->GetSiteInstance()));
 
   entry->SetHasPostData(params.is_post);
 
@@ -1248,7 +1251,8 @@ void NavigationControllerImpl::NavigateToPendingEntry(ReloadType reload_type) {
   // navigations to restored entries in TabContents::OnGoToEntryAtOffset.
   if (pending_entry_ && !pending_entry_->site_instance() &&
       pending_entry_->restore_type() != NavigationEntryImpl::RESTORE_NONE) {
-    pending_entry_->set_site_instance(tab_contents_->GetPendingSiteInstance());
+    pending_entry_->set_site_instance(static_cast<SiteInstanceImpl*>(
+        tab_contents_->GetPendingSiteInstance()));
     pending_entry_->set_restore_type(NavigationEntryImpl::RESTORE_NONE);
   }
 }
diff --git a/content/browser/tab_contents/navigation_controller_impl.h b/content/browser/tab_contents/navigation_controller_impl.h
index b8567f2..6c41b7e 100644
--- a/content/browser/tab_contents/navigation_controller_impl.h
+++ b/content/browser/tab_contents/navigation_controller_impl.h
@@ -14,13 +14,13 @@
 #include "content/public/browser/navigation_controller.h"
 #include "content/public/browser/navigation_type.h"
 
-class SiteInstance;
 class TabContents;
 struct ViewHostMsg_FrameNavigate_Params;
 
 namespace content {
 class NavigationEntryImpl;
 struct LoadCommittedDetails;
+class SiteInstance;
 }
 
 class CONTENT_EXPORT NavigationControllerImpl
@@ -100,13 +100,14 @@ class CONTENT_EXPORT NavigationControllerImpl
 
   // Return the index of the entry with the corresponding instance and page_id,
   // or -1 if not found.
-  int GetEntryIndexWithPageID(SiteInstance* instance,
+  int GetEntryIndexWithPageID(content::SiteInstance* instance,
                               int32 page_id) const;
 
   // Return the entry with the corresponding instance and page_id, or NULL if
   // not found.
-  content::NavigationEntryImpl* GetEntryWithPageID(SiteInstance* instance,
-                                                   int32 page_id) const;
+  content::NavigationEntryImpl* GetEntryWithPageID(
+      content::SiteInstance* instance,
+      int32 page_id) const;
 
   // Transient entry -----------------------------------------------------------
 
diff --git a/content/browser/tab_contents/navigation_controller_impl_unittest.cc b/content/browser/tab_contents/navigation_controller_impl_unittest.cc
index 340a19d..c99e5a5 100644
--- a/content/browser/tab_contents/navigation_controller_impl_unittest.cc
+++ b/content/browser/tab_contents/navigation_controller_impl_unittest.cc
@@ -17,7 +17,7 @@
 //  #include "chrome/browser/sessions/session_service_test_helper.h"
 //  #include "chrome/browser/sessions/session_types.h"
 #include "content/browser/renderer_host/test_render_view_host.h"
-#include "content/browser/site_instance.h"
+#include "content/browser/site_instance_impl.h"
 #include "content/browser/tab_contents/navigation_controller_impl.h"
 #include "content/browser/tab_contents/navigation_entry_impl.h"
 #include "content/browser/tab_contents/tab_contents.h"
@@ -37,6 +37,7 @@ using base::Time;
 using content::NavigationController;
 using content::NavigationEntry;
 using content::NavigationEntryImpl;
+using content::SiteInstance;
 using content::WebContents;
 
 // NavigationControllerTest ----------------------------------------------------
@@ -760,8 +761,9 @@ TEST_F(NavigationControllerTest, Back_OtherBackPending) {
 
   // We know all the entries have the same site instance, so we can just grab
   // a random one for looking up other entries.
-  SiteInstance* site_instance = NavigationEntryImpl::FromNavigationEntry(
-      controller.GetLastCommittedEntry())->site_instance();
+  SiteInstance* site_instance =
+      NavigationEntryImpl::FromNavigationEntry(
+          controller.GetLastCommittedEntry())->site_instance();
 
   // That second URL should be the last committed and it should have gotten the
   // new title.
@@ -1578,7 +1580,7 @@ TEST_F(NavigationControllerTest, RestoreNavigate) {
   EXPECT_EQ(url,
             NavigationEntryImpl::FromNavigationEntry(
                 our_controller.GetLastCommittedEntry())->site_instance()->
-                    site());
+                    GetSite());
   EXPECT_EQ(NavigationEntryImpl::RESTORE_NONE,
             NavigationEntryImpl::FromNavigationEntry(
                 our_controller.GetEntryAtIndex(0))->restore_type());
@@ -1658,7 +1660,7 @@ TEST_F(NavigationControllerTest, RestoreNavigateAfterFailure) {
   EXPECT_EQ(url,
             NavigationEntryImpl::FromNavigationEntry(
                 our_controller.GetLastCommittedEntry())->site_instance()->
-                    site());
+                    GetSite());
   EXPECT_EQ(NavigationEntryImpl::RESTORE_NONE,
             NavigationEntryImpl::FromNavigationEntry(
                 our_controller.GetEntryAtIndex(0))->restore_type());
diff --git a/content/browser/tab_contents/navigation_entry_impl.cc b/content/browser/tab_contents/navigation_entry_impl.cc
index e0b924c..f9bc0f7 100644
--- a/content/browser/tab_contents/navigation_entry_impl.cc
+++ b/content/browser/tab_contents/navigation_entry_impl.cc
@@ -6,12 +6,13 @@
 
 #include "base/string_util.h"
 #include "base/utf_string_conversions.h"
-#include "content/browser/site_instance.h"
 #include "content/public/common/content_constants.h"
 #include "content/public/common/url_constants.h"
 #include "net/base/net_util.h"
 #include "ui/base/text/text_elider.h"
 
+using content::SiteInstance;
+
 // Use this to get a new unique ID for a NavigationEntry during construction.
 // The returned ID is guaranteed to be nonzero (which is the "no ID" indicator).
 static int GetUniqueIDInConstructor() {
@@ -46,7 +47,7 @@ NavigationEntryImpl::NavigationEntryImpl()
       is_renderer_initiated_(false) {
 }
 
-NavigationEntryImpl::NavigationEntryImpl(SiteInstance* instance,
+NavigationEntryImpl::NavigationEntryImpl(SiteInstanceImpl* instance,
                                          int page_id,
                                          const GURL& url,
                                          const Referrer& referrer,
@@ -129,7 +130,7 @@ int32 NavigationEntryImpl::GetPageID() const {
   return page_id_;
 }
 
-void NavigationEntryImpl::set_site_instance(SiteInstance* site_instance) {
+void NavigationEntryImpl::set_site_instance(SiteInstanceImpl* site_instance) {
   site_instance_ = site_instance;
 }
 
diff --git a/content/browser/tab_contents/navigation_entry_impl.h b/content/browser/tab_contents/navigation_entry_impl.h
index c1c52e5..6d91e4b 100644
--- a/content/browser/tab_contents/navigation_entry_impl.h
+++ b/content/browser/tab_contents/navigation_entry_impl.h
@@ -8,13 +8,12 @@
 
 #include "base/basictypes.h"
 #include "base/memory/ref_counted.h"
+#include "content/browser/site_instance_impl.h"
 #include "content/public/browser/favicon_status.h"
 #include "content/public/browser/global_request_id.h"
 #include "content/public/browser/navigation_entry.h"
 #include "content/public/browser/ssl_status.h"
 
-class SiteInstance;
-
 namespace content {
 
 class CONTENT_EXPORT NavigationEntryImpl
@@ -23,7 +22,7 @@ class CONTENT_EXPORT NavigationEntryImpl
   static NavigationEntryImpl* FromNavigationEntry(NavigationEntry* entry);
 
   NavigationEntryImpl();
-  NavigationEntryImpl(SiteInstance* instance,
+  NavigationEntryImpl(SiteInstanceImpl* instance,
                       int page_id,
                       const GURL& url,
                       const Referrer& referrer,
@@ -71,9 +70,9 @@ class CONTENT_EXPORT NavigationEntryImpl
   // Note that the SiteInstance should usually not be changed after it is set,
   // but this may happen if the NavigationEntry was cloned and needs to use a
   // different SiteInstance.
-  void set_site_instance(SiteInstance* site_instance);
-  SiteInstance* site_instance() const {
-    return site_instance_;
+  void set_site_instance(SiteInstanceImpl* site_instance);
+  SiteInstanceImpl* site_instance() const {
+    return site_instance_.get();
   }
 
   void set_page_type(PageType page_type) {
@@ -152,7 +151,7 @@ class CONTENT_EXPORT NavigationEntryImpl
 
   // See the accessors above for descriptions.
   int unique_id_;
-  scoped_refptr<SiteInstance> site_instance_;
+  scoped_refptr<SiteInstanceImpl> site_instance_;
   PageType page_type_;
   GURL url_;
   Referrer referrer_;
diff --git a/content/browser/tab_contents/navigation_entry_impl_unittest.cc b/content/browser/tab_contents/navigation_entry_impl_unittest.cc
index dc8d9e9..425b45b 100644
--- a/content/browser/tab_contents/navigation_entry_impl_unittest.cc
+++ b/content/browser/tab_contents/navigation_entry_impl_unittest.cc
@@ -5,7 +5,7 @@
 #include "base/string16.h"
 #include "base/string_util.h"
 #include "base/utf_string_conversions.h"
-#include "content/browser/site_instance.h"
+#include "content/browser/site_instance_impl.h"
 #include "content/browser/tab_contents/navigation_entry_impl.h"
 #include "content/public/browser/ssl_status.h"
 #include "testing/gtest/include/gtest/gtest.h"
@@ -20,7 +20,7 @@ class NavigationEntryTest : public testing::Test {
   virtual void SetUp() {
     entry1_.reset(new NavigationEntryImpl);
 
-    instance_ = SiteInstance::CreateSiteInstance(NULL);
+    instance_ = static_cast<SiteInstanceImpl*>(SiteInstance::Create(NULL));
     entry2_.reset(new NavigationEntryImpl(
           instance_, 3,
           GURL("test:url"),
@@ -37,7 +37,7 @@ class NavigationEntryTest : public testing::Test {
   scoped_ptr<NavigationEntryImpl> entry1_;
   scoped_ptr<NavigationEntryImpl> entry2_;
   // SiteInstances are deleted when their NavigationEntries are gone.
-  SiteInstance* instance_;
+  SiteInstanceImpl* instance_;
 };
 
 // Test unique ID accessors
diff --git a/content/browser/tab_contents/render_view_host_manager.cc b/content/browser/tab_contents/render_view_host_manager.cc
index f2ea2ae..caaad5e 100644
--- a/content/browser/tab_contents/render_view_host_manager.cc
+++ b/content/browser/tab_contents/render_view_host_manager.cc
@@ -12,7 +12,7 @@
 #include "content/browser/renderer_host/render_view_host.h"
 #include "content/browser/renderer_host/render_view_host_factory.h"
 #include "content/browser/renderer_host/render_widget_host_view.h"
-#include "content/browser/site_instance.h"
+#include "content/browser/site_instance_impl.h"
 #include "content/browser/tab_contents/navigation_controller_impl.h"
 #include "content/browser/tab_contents/navigation_entry_impl.h"
 #include "content/browser/webui/web_ui_impl.h"
@@ -30,6 +30,7 @@
 using content::NavigationController;
 using content::NavigationEntry;
 using content::NavigationEntryImpl;
+using content::SiteInstance;
 
 RenderViewHostManager::RenderViewHostManager(
     content::RenderViewHostDelegate* render_view_delegate,
@@ -66,7 +67,7 @@ void RenderViewHostManager::Init(content::BrowserContext* browser_context,
   // immediately give this SiteInstance to a RenderViewHost so that it is
   // ref counted.
   if (!site_instance)
-    site_instance = SiteInstance::CreateSiteInstance(browser_context);
+    site_instance = SiteInstance::Create(browser_context);
   render_view_host_ = RenderViewHostFactory::Create(
       site_instance, render_view_delegate_, routing_id, delegate_->
       GetControllerForRenderManager().GetSessionStorageNamespace());
@@ -345,7 +346,7 @@ bool RenderViewHostManager::ShouldSwapProcessesForNavigation(
   // page and one isn't.  If there's no cur_entry, check the current RVH's
   // site, which might already be committed to a Web UI URL (such as the NTP).
   const GURL& current_url = (cur_entry) ? cur_entry->GetURL() :
-      render_view_host_->site_instance()->site();
+      render_view_host_->site_instance()->GetSite();
   content::BrowserContext* browser_context =
       delegate_->GetControllerForRenderManager().GetBrowserContext();
   const content::WebUIFactory* web_ui_factory =
@@ -407,26 +408,29 @@ SiteInstance* RenderViewHostManager::GetSiteInstanceForEntry(
       entry.GetTransitionType() == content::PAGE_TRANSITION_GENERATED)
     return curr_instance;
 
+  SiteInstanceImpl* curr_site_instance =
+      static_cast<SiteInstanceImpl*>(curr_instance);
+
   // If we haven't used our SiteInstance (and thus RVH) yet, then we can use it
   // for this entry.  We won't commit the SiteInstance to this site until the
   // navigation commits (in DidNavigate), unless the navigation entry was
   // restored or it's a Web UI as described below.
-  if (!curr_instance->has_site()) {
+  if (!curr_site_instance->HasSite()) {
     // If we've already created a SiteInstance for our destination, we don't
     // want to use this unused SiteInstance; use the existing one.  (We don't
     // do this check if the curr_instance has a site, because for now, we want
     // to compare against the current URL and not the SiteInstance's site.  In
     // this case, there is no current URL, so comparing against the site is ok.
     // See additional comments below.)
-    if (curr_instance->HasRelatedSiteInstance(dest_url))
-      return curr_instance->GetRelatedSiteInstance(dest_url);
+    if (curr_site_instance->HasRelatedSiteInstance(dest_url))
+      return curr_site_instance->GetRelatedSiteInstance(dest_url);
 
     // For extensions, Web UI URLs (such as the new tab page), and apps we do
     // not want to use the curr_instance if it has no site, since it will have a
     // RenderProcessHost of PRIV_NORMAL.  Create a new SiteInstance for this
     // URL instead (with the correct process type).
-    if (curr_instance->HasWrongProcessForURL(dest_url))
-      return curr_instance->GetRelatedSiteInstance(dest_url);
+    if (curr_site_instance->HasWrongProcessForURL(dest_url))
+      return curr_site_instance->GetRelatedSiteInstance(dest_url);
 
     // Normally the "site" on the SiteInstance is set lazily when the load
     // actually commits. This is to support better process sharing in case
@@ -437,9 +441,9 @@ SiteInstance* RenderViewHostManager::GetSiteInstanceForEntry(
     // we need to set the site first, otherwise after a restore none of the
     // pages would share renderers in process-per-site.
     if (entry.restore_type() != NavigationEntryImpl::RESTORE_NONE)
-      curr_instance->SetSite(dest_url);
+      curr_site_instance->SetSite(dest_url);
 
-    return curr_instance;
+    return curr_site_instance;
   }
 
   // Otherwise, only create a new SiteInstance for cross-site navigation.
@@ -469,13 +473,14 @@ SiteInstance* RenderViewHostManager::GetSiteInstanceForEntry(
   // the page to a different same-site URL.  (This seems very unlikely in
   // practice.)
   const GURL& current_url = (curr_entry) ? curr_entry->GetURL() :
-      curr_instance->site();
+      curr_instance->GetSite();
 
   // Use the current SiteInstance for same site navigations, as long as the
   // process type is correct.  (The URL may have been installed as an app since
   // the last time we visited it.)
   if (SiteInstance::IsSameWebSite(browser_context, current_url, dest_url) &&
-      !curr_instance->HasWrongProcessForURL(dest_url)) {
+      !static_cast<SiteInstanceImpl*>(curr_instance)->HasWrongProcessForURL(
+          dest_url)) {
     return curr_instance;
   } else if (ShouldSwapProcessesForNavigation(curr_entry, &entry)) {
     // When we're swapping, we need to force the site instance AND browsing
@@ -484,7 +489,7 @@ SiteInstance* RenderViewHostManager::GetSiteInstanceForEntry(
     // Pages), keeping them in the same process. When you navigate away from
     // that page, we want to explicity ignore that BrowsingInstance and group
     // this page into the appropriate SiteInstance for its URL.
-    return SiteInstance::CreateSiteInstanceForURL(browser_context, dest_url);
+    return SiteInstance::CreateForURL(browser_context, dest_url);
   } else {
     // Start the new renderer in a new SiteInstance, but in the current
     // BrowsingInstance.  It is important to immediately give this new
@@ -496,7 +501,7 @@ SiteInstance* RenderViewHostManager::GetSiteInstanceForEntry(
 }
 
 bool RenderViewHostManager::CreatePendingRenderView(
-    const NavigationEntryImpl& entry, SiteInstance* instance) {
+  const NavigationEntryImpl& entry, SiteInstance* instance) {
   NavigationEntry* curr_entry =
       delegate_->GetControllerForRenderManager().GetLastCommittedEntry();
   if (curr_entry) {
@@ -508,7 +513,7 @@ bool RenderViewHostManager::CreatePendingRenderView(
   // Check if we've already created an RVH for this SiteInstance.
   CHECK(instance);
   RenderViewHostMap::iterator iter =
-      swapped_out_hosts_.find(instance->id());
+      swapped_out_hosts_.find(instance->GetId());
   if (iter != swapped_out_hosts_.end()) {
     // Re-use the existing RenderViewHost, which has already been initialized.
     // We'll remove it from the list of swapped out hosts if it commits.
@@ -613,7 +618,7 @@ void RenderViewHostManager::CommitPending() {
       content::Details<std::pair<RenderViewHost*, RenderViewHost*> >(&details));
 
   // If the pending view was on the swapped out list, we can remove it.
-  swapped_out_hosts_.erase(render_view_host_->site_instance()->id());
+  swapped_out_hosts_.erase(render_view_host_->site_instance()->GetId());
 
   // If the old RVH is live, we are swapping it out and should keep track of it
   // in case we navigate back to it.
@@ -623,7 +628,7 @@ void RenderViewHostManager::CommitPending() {
     // sure we don't get different rvh instances for the same site instance
     // in the same rvhmgr.
     // TODO(creis): Clean this up.
-    int32 old_site_instance_id = old_render_view_host->site_instance()->id();
+    int32 old_site_instance_id = old_render_view_host->site_instance()->GetId();
     RenderViewHostMap::iterator iter =
         swapped_out_hosts_.find(old_site_instance_id);
     if (iter != swapped_out_hosts_.end() &&
@@ -815,6 +820,6 @@ bool RenderViewHostManager::IsSwappedOut(RenderViewHost* rvh) {
   if (!rvh->site_instance())
     return false;
 
-  return swapped_out_hosts_.find(rvh->site_instance()->id()) !=
+  return swapped_out_hosts_.find(rvh->site_instance()->GetId()) !=
       swapped_out_hosts_.end();
 }
diff --git a/content/browser/tab_contents/render_view_host_manager.h b/content/browser/tab_contents/render_view_host_manager.h
index ae15dca..027e2ce 100644
--- a/content/browser/tab_contents/render_view_host_manager.h
+++ b/content/browser/tab_contents/render_view_host_manager.h
@@ -9,7 +9,7 @@
 #include "base/basictypes.h"
 #include "base/logging.h"
 #include "base/memory/scoped_ptr.h"
-#include "content/browser/site_instance.h"
+#include "content/browser/site_instance_impl.h"
 #include "content/common/content_export.h"
 #include "content/public/browser/notification_observer.h"
 #include "content/public/browser/notification_registrar.h"
@@ -101,7 +101,7 @@ class CONTENT_EXPORT RenderViewHostManager
 
   // For arguments, see TabContents constructor.
   void Init(content::BrowserContext* browser_context,
-            SiteInstance* site_instance,
+            content::SiteInstance* site_instance,
             int routing_id);
 
   // Returns the currently active RenderViewHost.
@@ -220,14 +220,14 @@ class CONTENT_EXPORT RenderViewHostManager
   // Returns an appropriate SiteInstance object for the given NavigationEntry,
   // possibly reusing the current SiteInstance.
   // Never called if --process-per-tab is used.
-  SiteInstance* GetSiteInstanceForEntry(
+  content::SiteInstance* GetSiteInstanceForEntry(
       const content::NavigationEntryImpl& entry,
-      SiteInstance* curr_instance);
+      content::SiteInstance* curr_instance);
 
   // Helper method to create a pending RenderViewHost for a cross-site
   // navigation.
   bool CreatePendingRenderView(const content::NavigationEntryImpl& entry,
-                               SiteInstance* instance);
+                               content::SiteInstance* instance);
 
   // Sets up the necessary state for a new RenderViewHost navigating to the
   // given entry.
diff --git a/content/browser/tab_contents/render_view_host_manager_unittest.cc b/content/browser/tab_contents/render_view_host_manager_unittest.cc
index b7f1463..0891743 100644
--- a/content/browser/tab_contents/render_view_host_manager_unittest.cc
+++ b/content/browser/tab_contents/render_view_host_manager_unittest.cc
@@ -6,7 +6,7 @@
 #include "content/browser/browser_url_handler.h"
 #include "content/browser/mock_content_browser_client.h"
 #include "content/browser/renderer_host/test_render_view_host.h"
-#include "content/browser/site_instance.h"
+#include "content/browser/site_instance_impl.h"
 #include "content/browser/tab_contents/navigation_controller_impl.h"
 #include "content/browser/tab_contents/navigation_entry_impl.h"
 #include "content/browser/tab_contents/render_view_host_manager.h"
@@ -31,6 +31,7 @@ using content::BrowserThreadImpl;
 using content::NavigationController;
 using content::NavigationEntry;
 using content::NavigationEntryImpl;
+using content::SiteInstance;
 using content::WebContents;
 using content::WebUIController;
 
@@ -198,8 +199,10 @@ TEST_F(RenderViewHostManagerTest, NewTabPageProcesses) {
   // The two RVH's should be different in every way.
   EXPECT_NE(active_rvh()->process(), dest_rvh2->process());
   EXPECT_NE(active_rvh()->site_instance(), dest_rvh2->site_instance());
-  EXPECT_NE(active_rvh()->site_instance()->browsing_instance_,
-            dest_rvh2->site_instance()->browsing_instance_);
+  EXPECT_NE(static_cast<SiteInstanceImpl*>(active_rvh()->site_instance())->
+                browsing_instance_,
+            static_cast<SiteInstanceImpl*>(dest_rvh2->site_instance())->
+                browsing_instance_);
 
   // Navigate both to the new tab page, and verify that they share a
   // SiteInstance.
@@ -272,8 +275,9 @@ TEST_F(RenderViewHostManagerTest, AlwaysSendEnableViewSourceMode) {
 // Tests the Init function by checking the initial RenderViewHost.
 TEST_F(RenderViewHostManagerTest, Init) {
   // Using TestBrowserContext.
-  SiteInstance* instance = SiteInstance::CreateSiteInstance(browser_context());
-  EXPECT_FALSE(instance->has_site());
+  SiteInstanceImpl* instance =
+      static_cast<SiteInstanceImpl*>(SiteInstance::Create(browser_context()));
+  EXPECT_FALSE(instance->HasSite());
 
   TestTabContents tab_contents(browser_context(), instance);
   RenderViewHostManager manager(&tab_contents, &tab_contents);
@@ -293,7 +297,7 @@ TEST_F(RenderViewHostManagerTest, Init) {
 TEST_F(RenderViewHostManagerTest, Navigate) {
   TestNotificationTracker notifications;
 
-  SiteInstance* instance = SiteInstance::CreateSiteInstance(browser_context());
+  SiteInstance* instance = SiteInstance::Create(browser_context());
 
   TestTabContents tab_contents(browser_context(), instance);
   notifications.ListenFor(
@@ -325,8 +329,9 @@ TEST_F(RenderViewHostManagerTest, Navigate) {
   // Commit to SiteInstance should be delayed until RenderView commit.
   EXPECT_TRUE(host == manager.current_host());
   ASSERT_TRUE(host);
-  EXPECT_FALSE(host->site_instance()->has_site());
-  host->site_instance()->SetSite(kUrl1);
+  EXPECT_FALSE(static_cast<SiteInstanceImpl*>(host->site_instance())->
+      HasSite());
+  static_cast<SiteInstanceImpl*>(host->site_instance())->SetSite(kUrl1);
 
   // 2) Navigate to next site. -------------------------
   const GURL kUrl2("http://www.google.com/foo");
@@ -345,7 +350,8 @@ TEST_F(RenderViewHostManagerTest, Navigate) {
   manager.DidNavigateMainFrame(host);
   EXPECT_TRUE(host == manager.current_host());
   ASSERT_TRUE(host);
-  EXPECT_TRUE(host->site_instance()->has_site());
+  EXPECT_TRUE(static_cast<SiteInstanceImpl*>(host->site_instance())->
+      HasSite());
 
   // 3) Cross-site navigate to next site. --------------
   const GURL kUrl3("http://webkit.org/");
@@ -366,7 +372,8 @@ TEST_F(RenderViewHostManagerTest, Navigate) {
   manager.DidNavigateMainFrame(manager.pending_render_view_host());
   EXPECT_TRUE(host == manager.current_host());
   ASSERT_TRUE(host);
-  EXPECT_TRUE(host->site_instance()->has_site());
+  EXPECT_TRUE(static_cast<SiteInstanceImpl*>(host->site_instance())->
+      HasSite());
   // Check the pending RenderViewHost has been committed.
   EXPECT_FALSE(manager.pending_render_view_host());
 
@@ -382,7 +389,7 @@ TEST_F(RenderViewHostManagerTest, Navigate) {
 TEST_F(RenderViewHostManagerTest, NavigateWithEarlyReNavigation) {
   TestNotificationTracker notifications;
 
-  SiteInstance* instance = SiteInstance::CreateSiteInstance(browser_context());
+  SiteInstance* instance = SiteInstance::Create(browser_context());
 
   TestTabContents tab_contents(browser_context(), instance);
   notifications.ListenFor(
@@ -418,8 +425,9 @@ TEST_F(RenderViewHostManagerTest, NavigateWithEarlyReNavigation) {
   // Commit to SiteInstance should be delayed until RenderView commit.
   EXPECT_TRUE(host == manager.current_host());
   ASSERT_TRUE(host);
-  EXPECT_FALSE(host->site_instance()->has_site());
-  host->site_instance()->SetSite(kUrl1);
+  EXPECT_FALSE(static_cast<SiteInstanceImpl*>(host->site_instance())->
+      HasSite());
+  static_cast<SiteInstanceImpl*>(host->site_instance())->SetSite(kUrl1);
 
   // 2) Cross-site navigate to next site. -------------------------
   const GURL kUrl2("http://www.example.com");
@@ -502,7 +510,8 @@ TEST_F(RenderViewHostManagerTest, NavigateWithEarlyReNavigation) {
   manager.DidNavigateMainFrame(host3);
   EXPECT_TRUE(host3 == manager.current_host());
   ASSERT_TRUE(host3);
-  EXPECT_TRUE(host3->site_instance()->has_site());
+  EXPECT_TRUE(static_cast<SiteInstanceImpl*>(host3->site_instance())->
+      HasSite());
   // Check the pending RenderViewHost has been committed.
   EXPECT_FALSE(manager.pending_render_view_host());
 
@@ -515,7 +524,7 @@ TEST_F(RenderViewHostManagerTest, NavigateWithEarlyReNavigation) {
 TEST_F(RenderViewHostManagerTest, WebUI) {
   set_should_create_webui(true);
   BrowserThreadImpl ui_thread(BrowserThread::UI, MessageLoop::current());
-  SiteInstance* instance = SiteInstance::CreateSiteInstance(browser_context());
+  SiteInstance* instance = SiteInstance::Create(browser_context());
 
   TestTabContents tab_contents(browser_context(), instance);
   RenderViewHostManager manager(&tab_contents, &tab_contents);
@@ -537,8 +546,9 @@ TEST_F(RenderViewHostManagerTest, WebUI) {
   // as the navigation starts, rather than lazily after it commits, so we don't
   // try to re-use the SiteInstance/process for non DOM-UI things that may
   // get loaded in between.
-  EXPECT_TRUE(host->site_instance()->has_site());
-  EXPECT_EQ(kUrl, host->site_instance()->site());
+  EXPECT_TRUE(static_cast<SiteInstanceImpl*>(host->site_instance())->
+      HasSite());
+  EXPECT_EQ(kUrl, host->site_instance()->GetSite());
 
   // The Web UI is committed immediately because the RenderViewHost has not been
   // used yet. UpdateRendererStateForNavigate() took the short cut path.
@@ -555,7 +565,7 @@ TEST_F(RenderViewHostManagerTest, WebUI) {
 // Regression test for bug 46290.
 TEST_F(RenderViewHostManagerTest, NonWebUIChromeURLs) {
   BrowserThreadImpl thread(BrowserThread::UI, &message_loop_);
-  SiteInstance* instance = SiteInstance::CreateSiteInstance(browser_context());
+  SiteInstance* instance = SiteInstance::Create(browser_context());
   TestTabContents tab_contents(browser_context(), instance);
   RenderViewHostManager manager(&tab_contents, &tab_contents);
   manager.Init(browser_context(), instance, MSG_ROUTING_NONE);
diff --git a/content/browser/tab_contents/tab_contents.cc b/content/browser/tab_contents/tab_contents.cc
index 073c6e7..b6c4e85 100644
--- a/content/browser/tab_contents/tab_contents.cc
+++ b/content/browser/tab_contents/tab_contents.cc
@@ -27,7 +27,7 @@
 #include "content/browser/renderer_host/render_widget_host_view.h"
 #include "content/browser/renderer_host/resource_dispatcher_host.h"
 #include "content/browser/renderer_host/resource_request_details.h"
-#include "content/browser/site_instance.h"
+#include "content/browser/site_instance_impl.h"
 #include "content/browser/tab_contents/interstitial_page.h"
 #include "content/browser/tab_contents/navigation_entry_impl.h"
 #include "content/browser/tab_contents/provisional_load_details.h"
@@ -121,6 +121,7 @@ using content::NavigationEntry;
 using content::NavigationEntryImpl;
 using content::OpenURLParams;
 using content::RenderViewHostDelegate;
+using content::SiteInstance;
 using content::SSLStatus;
 using content::UserMetricsAction;
 using content::WebContents;
@@ -504,20 +505,20 @@ int32 TabContents::GetMaxPageID() {
 }
 
 int32 TabContents::GetMaxPageIDForSiteInstance(SiteInstance* site_instance) {
-  if (max_page_ids_.find(site_instance->id()) == max_page_ids_.end())
-    max_page_ids_[site_instance->id()] = -1;
+  if (max_page_ids_.find(site_instance->GetId()) == max_page_ids_.end())
+    max_page_ids_[site_instance->GetId()] = -1;
 
-  return max_page_ids_[site_instance->id()];
+  return max_page_ids_[site_instance->GetId()];
 }
 
 void TabContents::UpdateMaxPageID(int32 page_id) {
   UpdateMaxPageIDForSiteInstance(GetSiteInstance(), page_id);
 }
 
-void TabContents::UpdateMaxPageIDForSiteInstance(SiteInstance* site_instance,
-                                                 int32 page_id) {
+void TabContents::UpdateMaxPageIDForSiteInstance(
+    SiteInstance* site_instance, int32 page_id) {
   if (GetMaxPageIDForSiteInstance(site_instance) < page_id)
-    max_page_ids_[site_instance->id()] = page_id;
+    max_page_ids_[site_instance->GetId()] = page_id;
 }
 
 void TabContents::CopyMaxPageIDsFrom(TabContents* tab_contents) {
@@ -672,7 +673,7 @@ WebContents* TabContents::Clone() {
   // processes for some reason.
   TabContents* tc = new TabContents(
       GetBrowserContext(),
-      SiteInstance::CreateSiteInstance(GetBrowserContext()),
+      SiteInstance::Create(GetBrowserContext()),
       MSG_ROUTING_NONE, this, NULL);
   tc->GetControllerImpl().CopyStateFrom(controller_);
   return tc;
@@ -878,9 +879,10 @@ bool TabContents::NavigateToEntry(
   return true;
 }
 
-void TabContents::SetHistoryLengthAndPrune(const SiteInstance* site_instance,
-                                           int history_length,
-                                           int32 minimum_page_id) {
+void TabContents::SetHistoryLengthAndPrune(
+    const SiteInstance* site_instance,
+    int history_length,
+    int32 minimum_page_id) {
   // SetHistoryLengthAndPrune doesn't work when there are pending cross-site
   // navigations. Callers should ensure that this is the case.
   if (render_manager_.pending_render_view_host()) {
@@ -1396,7 +1398,8 @@ void TabContents::OnGoToEntryAtOffset(int offset) {
     // it in now that we know. This allows us to find the entry when it commits.
     if (!entry->site_instance() &&
         entry->restore_type() != NavigationEntryImpl::RESTORE_NONE) {
-      entry->set_site_instance(GetPendingSiteInstance());
+      entry->set_site_instance(
+          static_cast<SiteInstanceImpl*>(GetPendingSiteInstance()));
     }
   }
 }
@@ -1735,8 +1738,8 @@ void TabContents::DidNavigate(RenderViewHost* rvh,
     render_manager_.DidNavigateMainFrame(rvh);
 
   // Update the site of the SiteInstance if it doesn't have one yet.
-  if (!GetSiteInstance()->has_site())
-    GetSiteInstance()->SetSite(params.url);
+  if (!static_cast<SiteInstanceImpl*>(GetSiteInstance())->HasSite())
+    static_cast<SiteInstanceImpl*>(GetSiteInstance())->SetSite(params.url);
 
   // Need to update MIME type here because it's referred to in
   // UpdateNavigationCommands() called by RendererDidNavigate() to
diff --git a/content/browser/tab_contents/tab_contents.h b/content/browser/tab_contents/tab_contents.h
index 16d486b..5dda23e 100644
--- a/content/browser/tab_contents/tab_contents.h
+++ b/content/browser/tab_contents/tab_contents.h
@@ -35,11 +35,11 @@ class LoadNotificationDetails;
 class RenderViewHost;
 class SavePackage;
 class SessionStorageNamespace;
-class SiteInstance;
 struct ViewHostMsg_DidFailProvisionalLoadWithError_Params;
 
 namespace content {
 class DownloadItem;
+class SiteInstance;
 class WebContentsObserver;
 class WebContentsDelegate;
 class WebContentsView;
@@ -57,7 +57,7 @@ class CONTENT_EXPORT TabContents
  public:
   // See WebContents::Create for a description of these parameters.
   TabContents(content::BrowserContext* browser_context,
-              SiteInstance* site_instance,
+              content::SiteInstance* site_instance,
               int routing_id,
               const TabContents* base_tab_contents,
               SessionStorageNamespace* session_storage_namespace);
@@ -72,7 +72,7 @@ class CONTENT_EXPORT TabContents
 
   // Updates the max page ID for the given SiteInstance in this TabContents
   // to be at least |page_id|.
-  void UpdateMaxPageIDForSiteInstance(SiteInstance* site_instance,
+  void UpdateMaxPageIDForSiteInstance(content::SiteInstance* site_instance,
                                       int32 page_id);
 
   // Copy the current map of SiteInstance ID to max page ID from another tab.
@@ -140,9 +140,9 @@ class CONTENT_EXPORT TabContents
   virtual const string16& GetTitle() const OVERRIDE;
   virtual int32 GetMaxPageID() OVERRIDE;
   virtual int32 GetMaxPageIDForSiteInstance(
-      SiteInstance* site_instance) OVERRIDE;
-  virtual SiteInstance* GetSiteInstance() const OVERRIDE;
-  virtual SiteInstance* GetPendingSiteInstance() const OVERRIDE;
+      content::SiteInstance* site_instance) OVERRIDE;
+  virtual content::SiteInstance* GetSiteInstance() const OVERRIDE;
+  virtual content::SiteInstance* GetPendingSiteInstance() const OVERRIDE;
   virtual bool IsLoading() const OVERRIDE;
   virtual bool IsWaitingForResponse() const OVERRIDE;
   virtual const net::LoadStateWithParam& GetLoadState() const OVERRIDE;
@@ -484,9 +484,10 @@ class CONTENT_EXPORT TabContents
   // moves the current page_id to the last entry in the list if it's valid.
   // This is mainly used when a prerendered page is swapped into the current
   // tab. The method is virtual for testing.
-  virtual void SetHistoryLengthAndPrune(const SiteInstance* site_instance,
-                                        int merge_history_length,
-                                        int32 minimum_page_id);
+  virtual void SetHistoryLengthAndPrune(
+      const content::SiteInstance* site_instance,
+      int merge_history_length,
+      int32 minimum_page_id);
 
   // Misc non-view stuff -------------------------------------------------------
 
diff --git a/content/browser/tab_contents/tab_contents_unittest.cc b/content/browser/tab_contents/tab_contents_unittest.cc
index f9b98b0..d943c1f 100644
--- a/content/browser/tab_contents/tab_contents_unittest.cc
+++ b/content/browser/tab_contents/tab_contents_unittest.cc
@@ -8,7 +8,7 @@
 #include "content/browser/renderer_host/render_view_host.h"
 #include "content/browser/renderer_host/render_widget_host_view.h"
 #include "content/browser/renderer_host/test_render_view_host.h"
-#include "content/browser/site_instance.h"
+#include "content/browser/site_instance_impl.h"
 #include "content/browser/tab_contents/interstitial_page.h"
 #include "content/browser/tab_contents/navigation_entry_impl.h"
 #include "content/browser/tab_contents/test_tab_contents.h"
@@ -29,6 +29,7 @@
 using content::BrowserThread;
 using content::NavigationEntry;
 using content::NavigationEntryImpl;
+using content::SiteInstance;
 using content::WebContents;
 using content::WebUIController;
 using webkit::forms::PasswordForm;
@@ -168,7 +169,7 @@ class TestInterstitialPage : public InterstitialPage {
  protected:
   virtual RenderViewHost* CreateRenderViewHost() {
     return new TestRenderViewHost(
-        SiteInstance::CreateSiteInstance(tab()->GetBrowserContext()),
+        SiteInstance::Create(tab()->GetBrowserContext()),
         this, MSG_ROUTING_NONE);
   }
 
@@ -278,7 +279,7 @@ TEST_F(TabContentsTest, NTPViewSource) {
 // Test to ensure UpdateMaxPageID is working properly.
 TEST_F(TabContentsTest, UpdateMaxPageID) {
   SiteInstance* instance1 = contents()->GetSiteInstance();
-  scoped_refptr<SiteInstance> instance2(SiteInstance::CreateSiteInstance(NULL));
+  scoped_refptr<SiteInstance> instance2(SiteInstance::Create(NULL));
 
   // Starts at -1.
   EXPECT_EQ(-1, contents()->GetMaxPageID());
diff --git a/content/browser/tab_contents/test_tab_contents.cc b/content/browser/tab_contents/test_tab_contents.cc
index 0f3352d..bbced34 100644
--- a/content/browser/tab_contents/test_tab_contents.cc
+++ b/content/browser/tab_contents/test_tab_contents.cc
@@ -10,7 +10,7 @@
 #include "content/browser/renderer_host/mock_render_process_host.h"
 #include "content/browser/renderer_host/render_view_host.h"
 #include "content/browser/renderer_host/test_render_view_host.h"
-#include "content/browser/site_instance.h"
+#include "content/browser/site_instance_impl.h"
 #include "content/browser/tab_contents/navigation_entry_impl.h"
 #include "content/common/view_messages.h"
 #include "content/public/common/page_transition_types.h"
@@ -18,6 +18,7 @@
 #include "webkit/forms/password_form.h"
 
 using content::NavigationEntry;
+using content::SiteInstance;
 using content::WebContents;
 
 TestTabContents::TestTabContents(content::BrowserContext* browser_context,
@@ -86,7 +87,7 @@ bool TestTabContents::CreateRenderViewForRenderManager(
 WebContents* TestTabContents::Clone() {
   TabContents* tc = new TestTabContents(
       GetBrowserContext(),
-      SiteInstance::CreateSiteInstance(GetBrowserContext()));
+      SiteInstance::Create(GetBrowserContext()));
   tc->GetControllerImpl().CopyStateFrom(controller_);
   return tc;
 }
@@ -148,13 +149,15 @@ void TestTabContents::ExpectSetHistoryLengthAndPrune(
     int history_length,
     int32 min_page_id) {
   expect_set_history_length_and_prune_ = true;
-  expect_set_history_length_and_prune_site_instance_ = site_instance;
+  expect_set_history_length_and_prune_site_instance_ =
+      static_cast<const SiteInstanceImpl*>(site_instance);
   expect_set_history_length_and_prune_history_length_ = history_length;
   expect_set_history_length_and_prune_min_page_id_ = min_page_id;
 }
 
 void TestTabContents::SetHistoryLengthAndPrune(
-    const SiteInstance* site_instance, int history_length, int32 min_page_id) {
+    const SiteInstance* site_instance, int history_length,
+    int32 min_page_id) {
   EXPECT_TRUE(expect_set_history_length_and_prune_);
   expect_set_history_length_and_prune_ = false;
   EXPECT_EQ(expect_set_history_length_and_prune_site_instance_, site_instance);
diff --git a/content/browser/tab_contents/test_tab_contents.h b/content/browser/tab_contents/test_tab_contents.h
index f714f68..7f3a073 100644
--- a/content/browser/tab_contents/test_tab_contents.h
+++ b/content/browser/tab_contents/test_tab_contents.h
@@ -10,6 +10,7 @@
 #include "content/public/common/page_transition_types.h"
 #include "webkit/glue/webpreferences.h"
 
+class SiteInstanceImpl;
 class TestRenderViewHost;
 
 // Subclass TabContents to ensure it creates TestRenderViewHosts and does
@@ -17,7 +18,7 @@ class TestRenderViewHost;
 class TestTabContents : public TabContents {
  public:
   TestTabContents(content::BrowserContext* browser_context,
-                  SiteInstance* instance);
+                  content::SiteInstance* instance);
   virtual ~TestTabContents();
 
   TestRenderViewHost* pending_rvh() const;
@@ -81,22 +82,24 @@ class TestTabContents : public TabContents {
   // Establish expected arguments for |SetHistoryLengthAndPrune()|. When
   // |SetHistoryLengthAndPrune()| is called, the arguments are compared
   // with the expected arguments specified here.
-  void ExpectSetHistoryLengthAndPrune(const SiteInstance* site_instance,
-                                      int history_length,
-                                      int32 min_page_id);
+  void ExpectSetHistoryLengthAndPrune(
+      const content::SiteInstance* site_instance,
+      int history_length,
+      int32 min_page_id);
 
   // Compares the arguments passed in with the expected arguments passed in
   // to |ExpectSetHistoryLengthAndPrune()|.
-  virtual void SetHistoryLengthAndPrune(const SiteInstance* site_instance,
-                                        int history_length,
-                                        int32 min_page_id) OVERRIDE;
+  virtual void SetHistoryLengthAndPrune(
+      const content::SiteInstance* site_instance,
+      int history_length,
+      int32 min_page_id) OVERRIDE;
 
  private:
   content::RenderViewHostDelegate::View* delegate_view_override_;
 
   // Expectations for arguments of |SetHistoryLengthAndPrune()|.
   bool expect_set_history_length_and_prune_;
-  scoped_refptr<const SiteInstance>
+  scoped_refptr<const SiteInstanceImpl>
     expect_set_history_length_and_prune_site_instance_;
   int expect_set_history_length_and_prune_history_length_;
   int32 expect_set_history_length_and_prune_min_page_id_;
diff --git a/content/content_browser.gypi b/content/content_browser.gypi
index e0ba6e8..efbb363 100644
--- a/content/content_browser.gypi
+++ b/content/content_browser.gypi
@@ -90,6 +90,7 @@
     'public/browser/save_page_type.h',
     'public/browser/sensors.h',
     'public/browser/sensors_listener.h',
+    'public/browser/site_instance.h',
     'public/browser/ssl_status.cc',
     'public/browser/ssl_status.h',
     'public/browser/user_metrics.h',
@@ -575,8 +576,8 @@
     'browser/sensors/sensors_provider.h',
     'browser/sensors/sensors_provider_impl.cc',
     'browser/sensors/sensors_provider_impl.h',
-    'browser/site_instance.cc',
-    'browser/site_instance.h',
+    'browser/site_instance_impl.cc',
+    'browser/site_instance_impl.h',
     'browser/speech/audio_encoder.cc',
     'browser/speech/audio_encoder.h',
     'browser/speech/endpointer/endpointer.cc',
diff --git a/content/content_tests.gypi b/content/content_tests.gypi
index 8870015..9d9cb53 100644
--- a/content/content_tests.gypi
+++ b/content/content_tests.gypi
@@ -243,7 +243,7 @@
         'browser/renderer_host/resource_queue_unittest.cc',
         'browser/renderer_host/text_input_client_mac_unittest.mm',
         'browser/resolve_proxy_msg_helper_unittest.cc',
-        'browser/site_instance_unittest.cc',
+        'browser/site_instance_impl_unittest.cc',
         'browser/speech/endpointer/endpointer_unittest.cc',
         'browser/speech/speech_recognition_request_unittest.cc',
         'browser/speech/speech_recognizer_unittest.cc',
diff --git a/content/public/browser/content_browser_client.h b/content/public/browser/content_browser_client.h
index c83631b..d008bc0 100644
--- a/content/public/browser/content_browser_client.h
+++ b/content/public/browser/content_browser_client.h
@@ -23,7 +23,6 @@ class PluginProcessHost;
 class QuotaPermissionContext;
 class RenderViewHost;
 class ResourceDispatcherHost;
-class SiteInstance;
 class SSLCertErrorHandler;
 class SSLClientAuthHandler;
 class SkBitmap;
@@ -34,6 +33,7 @@ namespace content {
 class AccessTokenStore;
 class BrowserMainParts;
 class RenderProcessHost;
+class SiteInstance;
 class WebContents;
 class WebContentsView;
 struct MainFunctionParams;
@@ -123,10 +123,11 @@ class ContentBrowserClient {
                               const GURL& site_url) = 0;
 
   // Called when a site instance is first associated with a process.
-  virtual void SiteInstanceGotProcess(SiteInstance* site_instance) = 0;
+  virtual void SiteInstanceGotProcess(
+      content::SiteInstance* site_instance) = 0;
 
   // Called from a site instance's destructor.
-  virtual void SiteInstanceDeleting(SiteInstance* site_instance) = 0;
+  virtual void SiteInstanceDeleting(content::SiteInstance* site_instance) = 0;
 
   // Returns true if for the navigation from |current_url| to |new_url|,
   // processes should be swapped (even if we are in a process model that
diff --git a/content/browser/site_instance.h b/content/public/browser/site_instance.h
index 2a40762..37c6201 100644
--- a/content/browser/site_instance.h
+++ b/content/public/browser/site_instance.h
@@ -2,26 +2,23 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-#ifndef CONTENT_BROWSER_RENDERER_HOST_SITE_INSTANCE_H_
-#define CONTENT_BROWSER_RENDERER_HOST_SITE_INSTANCE_H_
+#ifndef CONTENT_PUBLIC_BROWSER_SITE_INSTANCE_H_
+#define CONTENT_PUBLIC_BROWSER_SITE_INSTANCE_H_
 #pragma once
 
-#include "content/browser/renderer_host/render_process_host_impl.h"
+#include "base/basictypes.h"
+#include "base/memory/ref_counted.h"
 #include "content/common/content_export.h"
-#include "content/public/browser/notification_observer.h"
-#include "content/public/browser/notification_registrar.h"
 #include "googleurl/src/gurl.h"
 
 class BrowsingInstance;
 
 namespace content {
 class BrowserContext;
-class RenderProcessHostFactory;
-}
+class RenderProcessHost;
 
 ///////////////////////////////////////////////////////////////////////////////
-//
-// SiteInstance class
+// SiteInstance interface.
 //
 // A SiteInstance is a data structure that is associated with all pages in a
 // given instance of a web site.  Here, a web site is identified by its
@@ -53,43 +50,26 @@ class RenderProcessHostFactory;
 // tabs with no NavigationEntries or in NavigationEntries in the history.
 //
 ///////////////////////////////////////////////////////////////////////////////
-class CONTENT_EXPORT SiteInstance : public base::RefCounted<SiteInstance>,
-                                    public content::NotificationObserver {
+class CONTENT_EXPORT SiteInstance : public base::RefCounted<SiteInstance> {
  public:
   // Returns a unique ID for this SiteInstance.
-  int32 id() { return id_; }
-
-  // Sets the factory used to create new RenderProcessHosts. This will also be
-  // passed on to SiteInstances spawned by this one.
-  //
-  // The factory must outlive the SiteInstance; ownership is not transferred. It
-  // may be NULL, in which case the default BrowserRenderProcessHost will be
-  // created (this is the behavior if you don't call this function).
-  void set_render_process_host_factory(
-      content::RenderProcessHostFactory* rph_factory) {
-    render_process_host_factory_ = rph_factory;
-  }
+  virtual int32 GetId() = 0;
 
   // Whether this SiteInstance has a running process associated with it.
-  bool HasProcess() const;
+  virtual bool HasProcess() const = 0;
 
   // Returns the current process being used to render pages in this
   // SiteInstance.  If the process has crashed or otherwise gone away, then
   // this method will create a new process and update our host ID accordingly.
-  content::RenderProcessHost* GetProcess();
+  virtual content::RenderProcessHost* GetProcess() = 0;
 
-  // Set / Get the web site that this SiteInstance is rendering pages for.
-  // This includes the scheme and registered domain, but not the port.  If the
-  // URL does not have a valid registered domain, then the full hostname is
-  // stored.
-  void SetSite(const GURL& url);
-  const GURL& site() const { return site_; }
-  bool has_site() const { return has_site_; }
+  // Browser context to which this SiteInstance (and all related
+  // SiteInstances) belongs.
+  virtual content::BrowserContext* GetBrowserContext() const = 0;
 
-  // Returns whether there is currently a related SiteInstance (registered with
-  // BrowsingInstance) for the site of the given url.  If so, we should try to
-  // avoid dedicating an unused SiteInstance to it (e.g., in a new tab).
-  bool HasRelatedSiteInstance(const GURL& url);
+  // Get the web site that this SiteInstance is rendering pages for.
+  // This includes the scheme and registered domain, but not the port.
+  virtual const GURL& GetSite() const = 0;
 
   // Gets a SiteInstance for the given URL that shares the current
   // BrowsingInstance, creating a new SiteInstance if necessary.  This ensures
@@ -100,16 +80,7 @@ class CONTENT_EXPORT SiteInstance : public base::RefCounted<SiteInstance>,
   // class from the rest of the codebase.)
   // TODO(creis): This may be an argument to build a pass_refptr<T> class, as
   // Darin suggests.
-  SiteInstance* GetRelatedSiteInstance(const GURL& url);
-
-  // Returns whether this SiteInstance has a process that is the wrong type for
-  // the given URL.  If so, the browser should force a process swap when
-  // navigating to the URL.
-  bool HasWrongProcessForURL(const GURL& url) const;
-
-  // Browser context to which this SiteInstance (and all related
-  // SiteInstances) belongs.
-  content::BrowserContext* GetBrowserContext() const;
+  virtual SiteInstance* GetRelatedSiteInstance(const GURL& url) = 0;
 
   // Factory method to create a new SiteInstance.  This will create a new
   // new BrowsingInstance, so it should only be used when creating a new tab
@@ -120,20 +91,15 @@ class CONTENT_EXPORT SiteInstance : public base::RefCounted<SiteInstance>,
   //
   // TODO(creis): This may be an argument to build a pass_refptr<T> class, as
   // Darin suggests.
-  static SiteInstance* CreateSiteInstance(
-      content::BrowserContext* browser_context);
+  static SiteInstance* Create(content::BrowserContext* browser_context);
 
   // Factory method to get the appropriate SiteInstance for the given URL, in
-  // a new BrowsingInstance.  Use this instead of CreateSiteInstance when you
-  // know the URL, since it allows special site grouping rules to be applied
-  // (for example, to group chrome-ui pages into the same instance).
-  static SiteInstance* CreateSiteInstanceForURL(
+  // a new BrowsingInstance.  Use this instead of Create when you know the URL,
+  // since it allows special site grouping rules to be applied (for example,
+  // to group chrome-ui pages into the same instance).
+  static SiteInstance* CreateForURL(
       content::BrowserContext* browser_context, const GURL& url);
 
-  // Returns the site for the given URL, which includes only the scheme and
-  // registered domain.  Returns an empty GURL if the URL has no host.
-  static GURL GetSiteForURL(content::BrowserContext* context, const GURL& url);
-
   // Return whether both URLs are part of the same web site, for the purpose of
   // assigning them to processes accordingly.  The decision is currently based
   // on the registered domain of the URLs (google.com, bbc.co.uk), as well as
@@ -146,59 +112,11 @@ class CONTENT_EXPORT SiteInstance : public base::RefCounted<SiteInstance>,
 
  protected:
   friend class base::RefCounted<SiteInstance>;
-  friend class BrowsingInstance;
-
-  // Virtual to allow tests to extend it.
-  virtual ~SiteInstance();
-
-  // Create a new SiteInstance.  Protected to give access to BrowsingInstance
-  // and tests; most callers should use CreateSiteInstance or
-  // GetRelatedSiteInstance instead.
-  explicit SiteInstance(BrowsingInstance* browsing_instance);
-
-  // Get the effective URL for the given actual URL.
-  static GURL GetEffectiveURL(content::BrowserContext* browser_context,
-                              const GURL& url);
 
- private:
-  // content::NotificationObserver implementation.
-  virtual void Observe(int type,
-                       const content::NotificationSource& source,
-                       const content::NotificationDetails& details) OVERRIDE;
-
-  // Used to restrict a process' origin access rights.
-  void LockToOrigin();
-
-  // The next available SiteInstance ID.
-  static int32 next_site_instance_id_;
-
-  // A unique ID for this SiteInstance.
-  int32 id_;
-
-  content::NotificationRegistrar registrar_;
-
-  // BrowsingInstance to which this SiteInstance belongs.
-  scoped_refptr<BrowsingInstance> browsing_instance_;
-
-  // Factory for new RenderProcessHosts, not owned by this class. NULL indiactes
-  // that the default BrowserRenderProcessHost should be created.
-  const content::RenderProcessHostFactory* render_process_host_factory_;
-
-  // Current RenderProcessHost that is rendering pages for this SiteInstance.
-  // This pointer will only change once the RenderProcessHost is destructed.  It
-  // will still remain the same even if the process crashes, since in that
-  // scenario the RenderProcessHost remains the same.
-  content::RenderProcessHost* process_;
-
-  // The web site that this SiteInstance is rendering pages for.
-  GURL site_;
-
-  // Whether SetSite has been called.
-  bool has_site_;
-
-  FRIEND_TEST_ALL_PREFIXES(RenderViewHostManagerTest, NewTabPageProcesses);
-
-  DISALLOW_COPY_AND_ASSIGN(SiteInstance);
+  SiteInstance() {}
+  virtual ~SiteInstance() {}
 };
 
-#endif  // CONTENT_BROWSER_RENDERER_HOST_SITE_INSTANCE_H_
+}  // namespace content.
+
+#endif  // CONTENT_PUBLIC_BROWSER_SITE_INSTANCE_H_
diff --git a/content/public/browser/web_contents.h b/content/public/browser/web_contents.h
index 393f984..2811e1df 100644
--- a/content/public/browser/web_contents.h
+++ b/content/public/browser/web_contents.h
@@ -21,7 +21,6 @@ class InterstitialPage;
 class RenderViewHost;
 class RenderWidgetHostView;
 class SessionStorageNamespace;
-class SiteInstance;
 
 namespace base {
 class PropertyBag;
@@ -44,6 +43,7 @@ class NavigationController;
 class RenderProcessHost;
 class WebContentsDelegate;
 struct RendererPreferences;
+class SiteInstance;
 struct SSLStatus;
 // TODO(jam): of course we will have to rename WebContentsView etc to use
 // WebContents.
@@ -136,7 +136,8 @@ class WebContents : public PageNavigator {
 
   // The max page ID for any page that the given SiteInstance has loaded in
   // this TabContents.
-  virtual int32 GetMaxPageIDForSiteInstance(SiteInstance* site_instance) = 0;
+  virtual int32 GetMaxPageIDForSiteInstance(
+      SiteInstance* site_instance) = 0;
 
   // Returns the SiteInstance associated with the current page.
   virtual SiteInstance* GetSiteInstance() const = 0;
diff --git a/content/shell/shell.h b/content/shell/shell.h
index bb2d9f2..c4b09f7 100644
--- a/content/shell/shell.h
+++ b/content/shell/shell.h
@@ -23,12 +23,11 @@ typedef struct _GtkToolItem GtkToolItem;
 #endif
 
 class GURL;
-class SiteInstance;
 class TabContents;
 
 namespace content {
-
 class BrowserContext;
+class SiteInstance;
 
 // This represents one window of the Content Shell, i.e. all the UI including
 // buttons and url bar, as well as the web content area.