Move ExtensionHost into extensions namespace

BUG=139042,117261


Review URL: https://chromiumcodereview.appspot.com/10824030

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@149295 0039d316-1c4b-4281-b951-d872f2087c98

55 files changed, 200 insertions, 153 deletions

diff --git a/chrome/browser/automation/automation_provider_observers.cc b/chrome/browser/automation/automation_provider_observers.cc
index d64b673e..d77903a 100644
--- a/chrome/browser/automation/automation_provider_observers.cc
+++ b/chrome/browser/automation/automation_provider_observers.cc
@@ -3076,7 +3076,8 @@ void ExtensionPopupObserver::Observe(
     return;
   }
 
-  ExtensionHost* host = content::Details<ExtensionHost>(details).ptr();
+  extensions::ExtensionHost* host =
+      content::Details<extensions::ExtensionHost>(details).ptr();
   if (host->extension_id() == extension_id_ &&
       host->extension_host_type() == chrome::VIEW_TYPE_EXTENSION_POPUP) {
     AutomationJSONReply(automation_, reply_message_.release())
diff --git a/chrome/browser/background/background_contents_service.cc b/chrome/browser/background/background_contents_service.cc
index cb07a5f..8726ebe 100644
--- a/chrome/browser/background/background_contents_service.cc
+++ b/chrome/browser/background/background_contents_service.cc
@@ -299,8 +299,8 @@ void BackgroundContentsService::Observe(
         extension =
           profile->GetExtensionService()->GetExtensionById(extension_id, false);
       } else {
-        ExtensionHost* extension_host =
-            content::Details<ExtensionHost>(details).ptr();
+        extensions::ExtensionHost* extension_host =
+            content::Details<extensions::ExtensionHost>(details).ptr();
         extension = extension_host->extension();
       }
       if (!extension)
diff --git a/chrome/browser/chrome_content_browser_client.cc b/chrome/browser/chrome_content_browser_client.cc
index fdae27e..7ef3266 100644
--- a/chrome/browser/chrome_content_browser_client.cc
+++ b/chrome/browser/chrome_content_browser_client.cc
@@ -628,7 +628,7 @@ bool ChromeContentBrowserClient::ShouldTryToUseExistingProcessHost(
     for (ExtensionProcessManager::const_iterator iter =
              epm->background_hosts().begin();
          iter != epm->background_hosts().end(); ++iter) {
-      ExtensionHost* host = *iter;
+      const extensions::ExtensionHost* host = *iter;
       process_ids.insert(host->render_process_host()->GetID());
     }
   }
diff --git a/chrome/browser/chromeos/extensions/file_handler_util.cc b/chrome/browser/chromeos/extensions/file_handler_util.cc
index 240e53d..126e585 100644
--- a/chrome/browser/chromeos/extensions/file_handler_util.cc
+++ b/chrome/browser/chromeos/extensions/file_handler_util.cc
@@ -395,7 +395,7 @@ class ExtensionTaskExecutor : public FileTaskExecutor {
                                         const GURL& file_system_root,
                                         const FileDefinitionList& file_list,
                                         int handler_pid_in,
-                                        ExtensionHost* host);
+                                        extensions::ExtensionHost* host);
 
   // Populates |handler_host_permissions| with file path-permissions pairs that
   // will be given to the handler extension host process.
@@ -795,7 +795,7 @@ void ExtensionTaskExecutor::SetupPermissionsAndDispatchEvent(
     const GURL& file_system_root,
     const FileDefinitionList& file_list,
     int handler_pid_in,
-    ExtensionHost* host) {
+    extensions::ExtensionHost* host) {
   int handler_pid = host ? host->render_process_host()->GetID() :
                            handler_pid_in;
 
diff --git a/chrome/browser/chromeos/extensions/file_handler_util.h b/chrome/browser/chromeos/extensions/file_handler_util.h
index 5936e2b..c0489fe 100644
--- a/chrome/browser/chromeos/extensions/file_handler_util.h
+++ b/chrome/browser/chromeos/extensions/file_handler_util.h
@@ -12,7 +12,6 @@
 #include "chrome/common/extensions/url_pattern_set.h"
 
 class Browser;
-class ExtensionHost;
 class FileBrowserHandler;
 class GURL;
 class Profile;
diff --git a/chrome/browser/content_settings/content_settings_platform_app_provider.cc b/chrome/browser/content_settings/content_settings_platform_app_provider.cc
index fef6da2..18a2e88 100644
--- a/chrome/browser/content_settings/content_settings_platform_app_provider.cc
+++ b/chrome/browser/content_settings/content_settings_platform_app_provider.cc
@@ -67,8 +67,8 @@ void PlatformAppProvider::Observe(int type,
                                   const content::NotificationDetails& details) {
   switch (type) {
     case chrome::NOTIFICATION_EXTENSION_HOST_CREATED: {
-      const ExtensionHost* host =
-          content::Details<ExtensionHost>(details).ptr();
+      const extensions::ExtensionHost* host =
+          content::Details<extensions::ExtensionHost>(details).ptr();
       if (host->extension()->is_platform_app())
         SetContentSettingForExtension(host->extension(), CONTENT_SETTING_BLOCK);
       break;
diff --git a/chrome/browser/extensions/alert_apitest.cc b/chrome/browser/extensions/alert_apitest.cc
index c2b8fc3..048a1dc 100644
--- a/chrome/browser/extensions/alert_apitest.cc
+++ b/chrome/browser/extensions/alert_apitest.cc
@@ -17,7 +17,8 @@ IN_PROC_BROWSER_TEST_F(ExtensionApiTest, AlertBasic) {
   ASSERT_TRUE(RunExtensionTest("alert")) << message_;
 
   const extensions::Extension* extension = GetSingleLoadedExtension();
-  ExtensionHost* host = browser()->profile()->GetExtensionProcessManager()->
+  extensions::ExtensionHost* host =
+      browser()->profile()->GetExtensionProcessManager()->
       GetBackgroundHostForExtension(extension->id());
   ASSERT_TRUE(host);
   host->render_view_host()->ExecuteJavascriptInWebFrame(string16(),
diff --git a/chrome/browser/extensions/api/runtime/runtime_api.h b/chrome/browser/extensions/api/runtime/runtime_api.h
index e5f6b04..e24c3a8 100644
--- a/chrome/browser/extensions/api/runtime/runtime_api.h
+++ b/chrome/browser/extensions/api/runtime/runtime_api.h
@@ -7,12 +7,11 @@
 
 #include "chrome/browser/extensions/extension_function.h"
 
-class ExtensionHost;
 class Profile;
 
 namespace extensions {
-
 class Extension;
+class ExtensionHost;
 
 class RuntimeEventRouter {
  public:
diff --git a/chrome/browser/extensions/event_router.h b/chrome/browser/extensions/event_router.h
index f0cf6ab..8abde96 100644
--- a/chrome/browser/extensions/event_router.h
+++ b/chrome/browser/extensions/event_router.h
@@ -20,7 +20,6 @@
 #include "ipc/ipc_sender.h"
 
 class GURL;
-class ExtensionHost;
 class ExtensionDevToolsManager;
 class Profile;
 
@@ -30,6 +29,8 @@ class RenderProcessHost;
 
 namespace extensions {
 class Extension;
+class ExtensionHost;
+
 struct Event;
 
 class EventRouter : public content::NotificationObserver,
diff --git a/chrome/browser/extensions/extension_bindings_apitest.cc b/chrome/browser/extensions/extension_bindings_apitest.cc
index 62312fb..3463d36 100644
--- a/chrome/browser/extensions/extension_bindings_apitest.cc
+++ b/chrome/browser/extensions/extension_bindings_apitest.cc
@@ -27,7 +27,7 @@ IN_PROC_BROWSER_TEST_F(ExtensionBrowserTest, LastError) {
   // Get the ExtensionHost that is hosting our background page.
   ExtensionProcessManager* manager =
       browser()->profile()->GetExtensionProcessManager();
-  ExtensionHost* host = FindHostWithPath(manager, "/bg.html", 1);
+  extensions::ExtensionHost* host = FindHostWithPath(manager, "/bg.html", 1);
 
   bool result = false;
   ASSERT_TRUE(content::ExecuteJavaScriptAndExtractBool(
diff --git a/chrome/browser/extensions/extension_browsertest.cc b/chrome/browser/extensions/extension_browsertest.cc
index eb319ca..32d8a4d 100644
--- a/chrome/browser/extensions/extension_browsertest.cc
+++ b/chrome/browser/extensions/extension_browsertest.cc
@@ -534,11 +534,11 @@ void ExtensionBrowserTest::NavigateInRenderer(content::WebContents* contents,
   EXPECT_EQ(url, contents->GetController().GetLastCommittedEntry()->GetURL());
 }
 
-ExtensionHost* ExtensionBrowserTest::FindHostWithPath(
+extensions::ExtensionHost* ExtensionBrowserTest::FindHostWithPath(
     ExtensionProcessManager* manager,
     const std::string& path,
     int expected_hosts) {
-  ExtensionHost* host = NULL;
+  extensions::ExtensionHost* host = NULL;
   int num_hosts = 0;
   ExtensionProcessManager::ExtensionHostSet background_hosts =
       manager->background_hosts();
diff --git a/chrome/browser/extensions/extension_browsertest.h b/chrome/browser/extensions/extension_browsertest.h
index c6eb36c..3f6c394 100644
--- a/chrome/browser/extensions/extension_browsertest.h
+++ b/chrome/browser/extensions/extension_browsertest.h
@@ -154,9 +154,9 @@ class ExtensionBrowserTest : virtual public InProcessBrowserTest,
   // Looks for an ExtensionHost whose URL has the given path component
   // (including leading slash).  Also verifies that the expected number of hosts
   // are loaded.
-  ExtensionHost* FindHostWithPath(ExtensionProcessManager* manager,
-                                  const std::string& path,
-                                  int expected_hosts);
+  extensions::ExtensionHost* FindHostWithPath(ExtensionProcessManager* manager,
+                                              const std::string& path,
+                                              int expected_hosts);
 
   // content::NotificationObserver
   virtual void Observe(int type,
diff --git a/chrome/browser/extensions/extension_crash_recovery_browsertest.cc b/chrome/browser/extensions/extension_crash_recovery_browsertest.cc
index e8a86b9..509d212 100644
--- a/chrome/browser/extensions/extension_crash_recovery_browsertest.cc
+++ b/chrome/browser/extensions/extension_crash_recovery_browsertest.cc
@@ -75,7 +75,7 @@ class ExtensionCrashRecoveryTest : public ExtensionBrowserTest {
     const Extension* extension =
         GetExtensionService()->extensions()->GetByID(extension_id);
     ASSERT_TRUE(extension);
-    ExtensionHost* extension_host = GetExtensionProcessManager()->
+    extensions::ExtensionHost* extension_host = GetExtensionProcessManager()->
         GetBackgroundHostForExtension(extension_id);
     ASSERT_TRUE(extension_host);
 
@@ -92,7 +92,7 @@ class ExtensionCrashRecoveryTest : public ExtensionBrowserTest {
     const Extension* extension =
         GetExtensionService()->extensions()->GetByID(extension_id);
     ASSERT_TRUE(extension);
-    ExtensionHost* extension_host = GetExtensionProcessManager()->
+    extensions::ExtensionHost* extension_host = GetExtensionProcessManager()->
         GetBackgroundHostForExtension(extension_id);
     ASSERT_TRUE(extension_host);
     ExtensionProcessManager::ViewSet all_views =
diff --git a/chrome/browser/extensions/extension_devtools_browsertests.cc b/chrome/browser/extensions/extension_devtools_browsertests.cc
index c21a280..c6f5477 100644
--- a/chrome/browser/extensions/extension_devtools_browsertests.cc
+++ b/chrome/browser/extensions/extension_devtools_browsertests.cc
@@ -31,6 +31,7 @@ using content::DevToolsAgentHostRegistry;
 using content::DevToolsClientHost;
 using content::DevToolsManager;
 using content::WebContents;
+using extensions::ExtensionHost;
 
 // Looks for an background ExtensionHost whose URL has the given path component
 // (including leading slash).  Also verifies that the expected number of hosts
diff --git a/chrome/browser/extensions/extension_host.cc b/chrome/browser/extensions/extension_host.cc
index 3d36a0b..88920d2 100644
--- a/chrome/browser/extensions/extension_host.cc
+++ b/chrome/browser/extensions/extension_host.cc
@@ -60,7 +60,8 @@ using content::OpenURLParams;
 using content::RenderViewHost;
 using content::SiteInstance;
 using content::WebContents;
-using extensions::ExtensionSystem;
+
+namespace extensions {
 
 // Helper class that rate-limits the creation of renderer processes for
 // ExtensionHosts, to avoid blocking the UI.
@@ -122,7 +123,7 @@ class ExtensionHost::ProcessCreationQueue {
 ////////////////
 // ExtensionHost
 
-ExtensionHost::ExtensionHost(const extensions::Extension* extension,
+ExtensionHost::ExtensionHost(const Extension* extension,
                              SiteInstance* site_instance,
                              const GURL& url,
                              chrome::ViewType host_type)
@@ -245,7 +246,7 @@ void ExtensionHost::LoadInitialURL() {
       !profile_->GetExtensionService()->IsBackgroundPageReady(extension_)) {
     // Make sure the background page loads before any others.
     registrar_.Add(this, chrome::NOTIFICATION_EXTENSION_BACKGROUND_PAGE_READY,
-                   content::Source<extensions::Extension>(extension_));
+                   content::Source<Extension>(extension_));
     return;
   }
 
@@ -275,9 +276,8 @@ void ExtensionHost::Observe(int type,
       // sent. NULL it out so that dirty pointer issues don't arise in cases
       // when multiple ExtensionHost objects pointing to the same Extension are
       // present.
-      if (extension_ ==
-          content::Details<extensions::UnloadedExtensionInfo>(
-              details)->extension) {
+      if (extension_ == content::Details<UnloadedExtensionInfo>(details)->
+          extension) {
         extension_ = NULL;
       }
       break;
@@ -599,3 +599,5 @@ void ExtensionHost::RenderViewReady() {
       content::Source<Profile>(profile_),
       content::Details<ExtensionHost>(this));
 }
+
+}  // namespace extensions
diff --git a/chrome/browser/extensions/extension_host.h b/chrome/browser/extensions/extension_host.h
index 6df6308..f3c1352 100644
--- a/chrome/browser/extensions/extension_host.h
+++ b/chrome/browser/extensions/extension_host.h
@@ -41,7 +41,6 @@ class SiteInstance;
 namespace extensions {
 class Extension;
 class WindowController;
-}
 
 // This class is the browser component of an extension component's RenderView.
 // It handles setting up the renderer process, if needed, with special
@@ -65,7 +64,7 @@ class ExtensionHost : public content::WebContentsDelegate,
   typedef ExtensionViewAndroid PlatformExtensionView;
 #endif
 
-  ExtensionHost(const extensions::Extension* extension,
+  ExtensionHost(const Extension* extension,
                 content::SiteInstance* site_instance,
                 const GURL& url, chrome::ViewType host_type);
   virtual ~ExtensionHost();
@@ -94,7 +93,7 @@ class ExtensionHost : public content::WebContentsDelegate,
   // instantiate Browser objects.
   void CreateView(Browser* browser);
 
-  const extensions::Extension* extension() const { return extension_; }
+  const Extension* extension() const { return extension_; }
   const std::string& extension_id() const { return extension_id_; }
   content::WebContents* host_contents() const { return host_contents_.get(); }
   content::RenderViewHost* render_view_host() const;
@@ -204,7 +203,7 @@ class ExtensionHost : public content::WebContentsDelegate,
   bool is_background_page() const { return !view(); }
 
   // The extension that we're hosting in this view.
-  const extensions::Extension* extension_;
+  const Extension* extension_;
 
   // Id of extension that we're hosting in this view.
   const std::string extension_id_;
@@ -256,4 +255,6 @@ class ExtensionHost : public content::WebContentsDelegate,
   DISALLOW_COPY_AND_ASSIGN(ExtensionHost);
 };
 
+}  // namespace extensions
+
 #endif  // CHROME_BROWSER_EXTENSIONS_EXTENSION_HOST_H_
diff --git a/chrome/browser/extensions/extension_host_mac.h b/chrome/browser/extensions/extension_host_mac.h
index 4337325..622fe4a 100644
--- a/chrome/browser/extensions/extension_host_mac.h
+++ b/chrome/browser/extensions/extension_host_mac.h
@@ -9,7 +9,6 @@
 
 namespace extensions {
 class Extension;
-}
 
 // TODO(mpcomplete): I don't know what this does or if it is needed anymore,
 // now that ExtensionHost is restructured to rely on WebContents.
@@ -28,4 +27,6 @@ class ExtensionHostMac : public ExtensionHost {
   DISALLOW_COPY_AND_ASSIGN(ExtensionHostMac);
 };
 
+}  // namespace extensions
+
 #endif  // CHROME_BROWSER_EXTENSIONS_EXTENSION_HOST_MAC_H_
diff --git a/chrome/browser/extensions/extension_host_mac.mm b/chrome/browser/extensions/extension_host_mac.mm
index c3096d1..bf862b7 100644
--- a/chrome/browser/extensions/extension_host_mac.mm
+++ b/chrome/browser/extensions/extension_host_mac.mm
@@ -1,4 +1,4 @@
-// Copyright (c) 2011 The Chromium Authors. All rights reserved.
+// 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.
 
@@ -12,6 +12,8 @@
 
 using content::NativeWebKeyboardEvent;
 
+namespace extensions {
+
 ExtensionHostMac::~ExtensionHostMac() {
   // If there is a popup open for this host's extension, close it.
   ExtensionPopupController* popup = [ExtensionPopupController popup];
@@ -35,3 +37,5 @@ void ExtensionHostMac::UnhandledKeyboardEvent(
   DCHECK([event_window isKindOfClass:[ChromeEventProcessingWindow class]]);
   [event_window redispatchKeyEvent:event.os_event];
 }
+
+}  // namespace extensions
diff --git a/chrome/browser/extensions/extension_infobar_delegate.cc b/chrome/browser/extensions/extension_infobar_delegate.cc
index 8f9d8c7..cf4dfcb 100644
--- a/chrome/browser/extensions/extension_infobar_delegate.cc
+++ b/chrome/browser/extensions/extension_infobar_delegate.cc
@@ -92,7 +92,8 @@ void ExtensionInfoBarDelegate::Observe(
     const content::NotificationSource& source,
     const content::NotificationDetails& details) {
   if (type == chrome::NOTIFICATION_EXTENSION_HOST_VIEW_SHOULD_CLOSE) {
-    if (extension_host_.get() == content::Details<ExtensionHost>(details).ptr())
+    if (extension_host_.get() ==
+        content::Details<extensions::ExtensionHost>(details).ptr())
       RemoveSelf();
   } else {
     DCHECK(type == chrome::NOTIFICATION_EXTENSION_UNLOADED);
diff --git a/chrome/browser/extensions/extension_infobar_delegate.h b/chrome/browser/extensions/extension_infobar_delegate.h
index 76d997c..edf2f59 100644
--- a/chrome/browser/extensions/extension_infobar_delegate.h
+++ b/chrome/browser/extensions/extension_infobar_delegate.h
@@ -1,4 +1,4 @@
-// Copyright (c) 2011 The Chromium Authors. All rights reserved.
+// 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.
 
@@ -11,11 +11,11 @@
 #include "content/public/browser/notification_registrar.h"
 
 class Browser;
-class ExtensionHost;
 class GURL;
 
 namespace extensions {
 class Extension;
+class ExtensionHost;
 }
 
 // The InfobarDelegate for creating and managing state for the ExtensionInfobar
@@ -39,7 +39,7 @@ class ExtensionInfoBarDelegate : public InfoBarDelegate,
                            int height);
 
   const extensions::Extension* extension() { return extension_; }
-  ExtensionHost* extension_host() { return extension_host_.get(); }
+  extensions::ExtensionHost* extension_host() { return extension_host_.get(); }
   int height() { return height_; }
 
   void set_observer(DelegateObserver* observer) { observer_ = observer; }
@@ -67,7 +67,7 @@ class ExtensionInfoBarDelegate : public InfoBarDelegate,
   // own this since the InfoBar gets deleted and recreated when you switch tabs
   // and come back (and we don't want the user's interaction with the InfoBar to
   // get lost at that point).
-  scoped_ptr<ExtensionHost> extension_host_;
+  scoped_ptr<extensions::ExtensionHost> extension_host_;
 
   // The observer monitoring when the delegate dies.
   DelegateObserver* observer_;
diff --git a/chrome/browser/extensions/extension_management_browsertest.cc b/chrome/browser/extensions/extension_management_browsertest.cc
index 0251982..0bae022 100644
--- a/chrome/browser/extensions/extension_management_browsertest.cc
+++ b/chrome/browser/extensions/extension_management_browsertest.cc
@@ -44,7 +44,7 @@ class ExtensionManagementTest : public ExtensionBrowserTest {
     // sync with the Extension.
     ExtensionProcessManager* manager = browser()->profile()->
         GetExtensionProcessManager();
-    ExtensionHost* ext_host =
+    extensions::ExtensionHost* ext_host =
         manager->GetBackgroundHostForExtension(extension->id());
     EXPECT_TRUE(ext_host);
     if (!ext_host)
diff --git a/chrome/browser/extensions/extension_process_manager.cc b/chrome/browser/extensions/extension_process_manager.cc
index 6afa751..e9562e9 100644
--- a/chrome/browser/extensions/extension_process_manager.cc
+++ b/chrome/browser/extensions/extension_process_manager.cc
@@ -46,6 +46,7 @@ using content::RenderViewHost;
 using content::SiteInstance;
 using content::WebContents;
 using extensions::Extension;
+using extensions::ExtensionHost;
 
 namespace {
 
@@ -210,8 +211,8 @@ ExtensionHost* ExtensionProcessManager::CreateViewHost(
   EnsureBrowserWhenRequired(browser, view_type);
   ExtensionHost* host =
 #if defined(OS_MACOSX)
-      new ExtensionHostMac(extension, GetSiteInstanceForURL(url), url,
-                           view_type);
+      new extensions::ExtensionHostMac(
+          extension, GetSiteInstanceForURL(url), url, view_type);
 #else
       new ExtensionHost(extension, GetSiteInstanceForURL(url), url, view_type);
 #endif
@@ -276,8 +277,9 @@ void ExtensionProcessManager::CreateBackgroundHost(
 
   ExtensionHost* host =
 #if defined(OS_MACOSX)
-      new ExtensionHostMac(extension, GetSiteInstanceForURL(url), url,
-                           chrome::VIEW_TYPE_EXTENSION_BACKGROUND_PAGE);
+      new extensions::ExtensionHostMac(
+          extension, GetSiteInstanceForURL(url), url,
+          chrome::VIEW_TYPE_EXTENSION_BACKGROUND_PAGE);
 #else
       new ExtensionHost(extension, GetSiteInstanceForURL(url), url,
                         chrome::VIEW_TYPE_EXTENSION_BACKGROUND_PAGE);
diff --git a/chrome/browser/extensions/extension_process_manager.h b/chrome/browser/extensions/extension_process_manager.h
index 80e8e5a..ffff6fb 100644
--- a/chrome/browser/extensions/extension_process_manager.h
+++ b/chrome/browser/extensions/extension_process_manager.h
@@ -18,7 +18,6 @@
 #include "content/public/browser/notification_registrar.h"
 
 class Browser;
-class ExtensionHost;
 class GURL;
 class Profile;
 
@@ -29,6 +28,7 @@ class SiteInstance;
 
 namespace extensions {
 class Extension;
+class ExtensionHost;
 }
 
 // Manages dynamic state of running Chromium extensions. There is one instance
@@ -36,7 +36,7 @@ class Extension;
 // track of split-mode extensions only.
 class ExtensionProcessManager : public content::NotificationObserver {
  public:
-  typedef std::set<ExtensionHost*> ExtensionHostSet;
+  typedef std::set<extensions::ExtensionHost*> ExtensionHostSet;
   typedef ExtensionHostSet::const_iterator const_iterator;
 
   static ExtensionProcessManager* Create(Profile* profile);
@@ -52,23 +52,26 @@ class ExtensionProcessManager : public content::NotificationObserver {
   // Creates a new ExtensionHost with its associated view, grouping it in the
   // appropriate SiteInstance (and therefore process) based on the URL and
   // profile.
-  virtual ExtensionHost* CreateViewHost(const extensions::Extension* extension,
-                                        const GURL& url,
-                                        Browser* browser,
-                                        chrome::ViewType view_type);
-  ExtensionHost* CreateViewHost(const GURL& url,
+  virtual extensions::ExtensionHost* CreateViewHost(
+      const extensions::Extension* extension,
+      const GURL& url,
+      Browser* browser,
+      chrome::ViewType view_type);
+  extensions::ExtensionHost* CreateViewHost(const GURL& url,
                                 Browser* browser,
                                 chrome::ViewType view_type);
-  ExtensionHost* CreatePopupHost(const extensions::Extension* extension,
-                                 const GURL& url,
-                                 Browser* browser);
-  ExtensionHost* CreatePopupHost(const GURL& url, Browser* browser);
-  ExtensionHost* CreateDialogHost(const GURL& url);
-  ExtensionHost* CreateInfobarHost(const extensions::Extension* extension,
-                                   const GURL& url,
-                                   Browser* browser);
-  ExtensionHost* CreateInfobarHost(const GURL& url,
-                                   Browser* browser);
+  extensions::ExtensionHost* CreatePopupHost(
+      const extensions::Extension* extension,
+      const GURL& url,
+      Browser* browser);
+  extensions::ExtensionHost* CreatePopupHost(const GURL& url, Browser* browser);
+  extensions::ExtensionHost* CreateDialogHost(const GURL& url);
+  extensions::ExtensionHost* CreateInfobarHost(
+      const extensions::Extension* extension,
+      const GURL& url,
+      Browser* browser);
+  extensions::ExtensionHost* CreateInfobarHost(const GURL& url,
+                                               Browser* browser);
 
   // Open the extension's options page.
   void OpenOptionsPage(const extensions::Extension* extension,
@@ -81,7 +84,8 @@ class ExtensionProcessManager : public content::NotificationObserver {
 
   // Gets the ExtensionHost for the background page for an extension, or NULL if
   // the extension isn't running or doesn't have a background page.
-  ExtensionHost* GetBackgroundHostForExtension(const std::string& extension_id);
+  extensions::ExtensionHost* GetBackgroundHostForExtension(
+      const std::string& extension_id);
 
   // Returns the SiteInstance that the given URL belongs to.
   // TODO(aa): This only returns correct results for extensions and packaged
@@ -140,7 +144,8 @@ class ExtensionProcessManager : public content::NotificationObserver {
   explicit ExtensionProcessManager(Profile* profile);
 
   // Called just after |host| is created so it can be registered in our lists.
-  void OnExtensionHostCreated(ExtensionHost* host, bool is_background);
+  void OnExtensionHostCreated(extensions::ExtensionHost* host,
+                              bool is_background);
 
   // Called on browser shutdown to close our extension hosts.
   void CloseBackgroundHosts();
@@ -178,7 +183,7 @@ class ExtensionProcessManager : public content::NotificationObserver {
   ExtensionRenderViews all_extension_views_;
 
   // Close the given |host| iff it's a background page.
-  void CloseBackgroundHost(ExtensionHost* host);
+  void CloseBackgroundHost(extensions::ExtensionHost* host);
 
   // Ensure browser object is not null except for certain situations.
   void EnsureBrowserWhenRequired(Browser* browser,
diff --git a/chrome/browser/extensions/extension_service.cc b/chrome/browser/extensions/extension_service.cc
index b4f927a..a4da7a8 100644
--- a/chrome/browser/extensions/extension_service.cc
+++ b/chrome/browser/extensions/extension_service.cc
@@ -635,7 +635,8 @@ void ExtensionService::ReloadExtension(const std::string& extension_id) {
     // later.
     // TODO(yoz): this is not incognito-safe!
     ExtensionProcessManager* manager = system_->process_manager();
-    ExtensionHost* host = manager->GetBackgroundHostForExtension(extension_id);
+    extensions::ExtensionHost* host =
+        manager->GetBackgroundHostForExtension(extension_id);
     if (host && DevToolsAgentHostRegistry::HasDevToolsAgentHost(
             host->render_view_host())) {
       // Look for an open inspector for the background page.
@@ -2313,7 +2314,7 @@ void ExtensionService::ReportExtensionLoadError(
 }
 
 void ExtensionService::DidCreateRenderViewForBackgroundPage(
-    ExtensionHost* host) {
+    extensions::ExtensionHost* host) {
   OrphanedDevTools::iterator iter =
       orphaned_dev_tools_.find(host->extension_id());
   if (iter == orphaned_dev_tools_.end())
@@ -2336,7 +2337,8 @@ void ExtensionService::Observe(int type,
         break;
       }
 
-      ExtensionHost* host = content::Details<ExtensionHost>(details).ptr();
+      extensions::ExtensionHost* host =
+          content::Details<extensions::ExtensionHost>(details).ptr();
 
       // Mark the extension as terminated and Unload it. We want it to
       // be in a consistent state: either fully working or not loaded
diff --git a/chrome/browser/extensions/extension_service.h b/chrome/browser/extensions/extension_service.h
index 7e082c8..c6fee79 100644
--- a/chrome/browser/extensions/extension_service.h
+++ b/chrome/browser/extensions/extension_service.h
@@ -527,7 +527,7 @@ class ExtensionService
 
   // ExtensionHost of background page calls this method right after its render
   // view has been created.
-  void DidCreateRenderViewForBackgroundPage(ExtensionHost* host);
+  void DidCreateRenderViewForBackgroundPage(extensions::ExtensionHost* host);
 
   // For the extension in |version_path| with |id|, check to see if it's an
   // externally managed extension.  If so, uninstall it.
diff --git a/chrome/browser/extensions/gpu_browsertest.cc b/chrome/browser/extensions/gpu_browsertest.cc
index 24b3759..e04d9ae 100644
--- a/chrome/browser/extensions/gpu_browsertest.cc
+++ b/chrome/browser/extensions/gpu_browsertest.cc
@@ -23,7 +23,8 @@ IN_PROC_BROWSER_TEST_F(ExtensionBrowserTest, WebKitPrefsBackgroundPage) {
 
   ExtensionProcessManager* manager =
       browser()->profile()->GetExtensionProcessManager();
-  ExtensionHost* host = FindHostWithPath(manager, "/backgroundpage.html", 1);
+  extensions::ExtensionHost* host =
+      FindHostWithPath(manager, "/backgroundpage.html", 1);
   webkit_glue::WebPreferences prefs =
       host->render_view_host()->GetWebkitPreferences();
   ASSERT_TRUE(prefs.experimental_webgl_enabled);
diff --git a/chrome/browser/extensions/lazy_background_page_apitest.cc b/chrome/browser/extensions/lazy_background_page_apitest.cc
index c79671c..cc65747 100644
--- a/chrome/browser/extensions/lazy_background_page_apitest.cc
+++ b/chrome/browser/extensions/lazy_background_page_apitest.cc
@@ -241,7 +241,7 @@ IN_PROC_BROWSER_TEST_F(LazyBackgroundPageApiTest, WaitForRequest) {
   // Lazy Background Page still exists, because the extension started a request.
   ExtensionProcessManager* pm =
       browser()->profile()->GetExtensionProcessManager();
-  ExtensionHost* host =
+  extensions::ExtensionHost* host =
       pm->GetBackgroundHostForExtension(last_loaded_extension_id_);
   ASSERT_TRUE(host);
 
diff --git a/chrome/browser/extensions/lazy_background_task_queue.cc b/chrome/browser/extensions/lazy_background_task_queue.cc
index 89bf38e..b449f88 100644
--- a/chrome/browser/extensions/lazy_background_task_queue.cc
+++ b/chrome/browser/extensions/lazy_background_task_queue.cc
@@ -143,7 +143,8 @@ void LazyBackgroundTaskQueue::Observe(
     case chrome::NOTIFICATION_EXTENSION_HOST_DID_STOP_LOADING: {
       // If an on-demand background page finished loading, dispatch queued up
       // events for it.
-      ExtensionHost* host = content::Details<ExtensionHost>(details).ptr();
+      ExtensionHost* host =
+          content::Details<ExtensionHost>(details).ptr();
       if (host->extension_host_type() ==
               chrome::VIEW_TYPE_EXTENSION_BACKGROUND_PAGE) {
         CHECK(host->did_stop_loading());
@@ -153,7 +154,8 @@ void LazyBackgroundTaskQueue::Observe(
     }
     case chrome::NOTIFICATION_EXTENSION_HOST_DESTROYED: {
       Profile* profile = content::Source<Profile>(source).ptr();
-      ExtensionHost* host = content::Details<ExtensionHost>(details).ptr();
+      ExtensionHost* host =
+           content::Details<ExtensionHost>(details).ptr();
       if (host->extension_host_type() ==
               chrome::VIEW_TYPE_EXTENSION_BACKGROUND_PAGE) {
         PendingTasksKey key(profile,  host->extension()->id());
diff --git a/chrome/browser/extensions/lazy_background_task_queue.h b/chrome/browser/extensions/lazy_background_task_queue.h
index 04f0b91..55980b7 100644
--- a/chrome/browser/extensions/lazy_background_task_queue.h
+++ b/chrome/browser/extensions/lazy_background_task_queue.h
@@ -16,12 +16,11 @@
 #include "content/public/browser/notification_observer.h"
 #include "content/public/browser/notification_registrar.h"
 
-class ExtensionHost;
 class Profile;
 
 namespace extensions {
-
 class Extension;
+class ExtensionHost;
 
 // This class maintains a queue of tasks that should execute when an
 // extension's lazy background page is loaded. It is also in charge of loading
diff --git a/chrome/browser/extensions/message_service.h b/chrome/browser/extensions/message_service.h
index 381f15a..47a3116 100644
--- a/chrome/browser/extensions/message_service.h
+++ b/chrome/browser/extensions/message_service.h
@@ -14,7 +14,6 @@
 #include "content/public/browser/notification_observer.h"
 #include "content/public/browser/notification_registrar.h"
 
-class ExtensionHost;
 class Profile;
 
 namespace content {
@@ -23,6 +22,7 @@ class WebContents;
 }
 
 namespace extensions {
+class ExtensionHost;
 class LazyBackgroundTaskQueue;
 
 // This class manages message and event passing between renderer processes.
@@ -123,16 +123,16 @@ class MessageService : public content::NotificationObserver {
   // use that argument.
   void PendingOpenChannel(const OpenChannelParams& params,
                           int source_process_id,
-                          ExtensionHost* host);
+                          extensions::ExtensionHost* host);
   void PendingCloseChannel(int port_id,
                            bool connection_error,
-                           ExtensionHost* host) {
+                           extensions::ExtensionHost* host) {
     if (host)
       CloseChannel(port_id, connection_error);
   }
   void PendingPostMessage(int port_id,
                           const std::string& message,
-                          ExtensionHost* host) {
+                          extensions::ExtensionHost* host) {
     if (host)
       PostMessageFromRenderer(port_id, message);
   }
diff --git a/chrome/browser/extensions/platform_app_launcher.cc b/chrome/browser/extensions/platform_app_launcher.cc
index dd6a49b..d50fdec 100644
--- a/chrome/browser/extensions/platform_app_launcher.cc
+++ b/chrome/browser/extensions/platform_app_launcher.cc
@@ -172,7 +172,7 @@ class PlatformAppCommandLineLauncher
 
     ExtensionProcessManager* process_manager =
         ExtensionSystem::Get(profile_)->process_manager();
-    ExtensionHost* host =
+    extensions::ExtensionHost* host =
         process_manager->GetBackgroundHostForExtension(extension_->id());
     DCHECK(host);
     GrantAccessToFileAndLaunch(file_path, mime_type, host);
@@ -180,7 +180,7 @@ class PlatformAppCommandLineLauncher
 
   void GrantAccessToFileAndLaunch(const FilePath& file_path,
                                   const std::string& mime_type,
-                                  ExtensionHost* host) {
+                                  extensions::ExtensionHost* host) {
     // If there was an error loading the app page, |host| will be NULL.
     if (!host) {
       LOG(ERROR) << "Could not load app page for " << extension_->id();
@@ -260,7 +260,7 @@ class PlatformAppBlobIntentLauncher
 
     ExtensionProcessManager* process_manager =
         ExtensionSystem::Get(profile_)->process_manager();
-    ExtensionHost* host =
+    extensions::ExtensionHost* host =
         process_manager->GetBackgroundHostForExtension(extension_->id());
     DCHECK(host);
     GrantAccessToFileAndLaunch(host);
@@ -271,7 +271,7 @@ class PlatformAppBlobIntentLauncher
 
   virtual ~PlatformAppBlobIntentLauncher() {}
 
-  void GrantAccessToFileAndLaunch(ExtensionHost* host) {
+  void GrantAccessToFileAndLaunch(extensions::ExtensionHost* host) {
     // If there was an error loading the app page, |host| will be NULL.
     if (!host) {
       LOG(ERROR) << "Could not load app page for " << extension_->id();
diff --git a/chrome/browser/file_select_helper.h b/chrome/browser/file_select_helper.h
index 72674a5..0f0d8e0 100644
--- a/chrome/browser/file_select_helper.h
+++ b/chrome/browser/file_select_helper.h
@@ -28,8 +28,8 @@ struct SelectedFileInfo;
 }
 
 // This class handles file-selection requests coming from WebUI elements
-// (via the ExtensionHost class). It implements both the initialisation
-// and listener functions for file-selection dialogs.
+// (via the extensions::ExtensionHost class). It implements both the
+// initialisation and listener functions for file-selection dialogs.
 class FileSelectHelper
     : public base::RefCountedThreadSafe<FileSelectHelper>,
       public ui::SelectFileDialog::Listener,
diff --git a/chrome/browser/speech/speech_input_extension_manager.cc b/chrome/browser/speech/speech_input_extension_manager.cc
index a8a27fb..4f9dac9 100644
--- a/chrome/browser/speech/speech_input_extension_manager.cc
+++ b/chrome/browser/speech/speech_input_extension_manager.cc
@@ -255,7 +255,8 @@ int SpeechInputExtensionManager::GetRenderProcessIDForExtension(
   ExtensionProcessManager* epm =
       extensions::ExtensionSystem::Get(profile_)->process_manager();
   DCHECK(epm);
-  ExtensionHost* eh = epm->GetBackgroundHostForExtension(extension_id);
+  extensions::ExtensionHost* eh =
+      epm->GetBackgroundHostForExtension(extension_id);
   DCHECK(eh);
   content::RenderProcessHost* rph = eh->render_process_host();
   DCHECK(rph);
diff --git a/chrome/browser/task_manager/task_manager_resource_providers.cc b/chrome/browser/task_manager/task_manager_resource_providers.cc
index 3f455a9..7233805 100644
--- a/chrome/browser/task_manager/task_manager_resource_providers.cc
+++ b/chrome/browser/task_manager/task_manager_resource_providers.cc
@@ -1490,7 +1490,8 @@ void TaskManagerExtensionProcessResourceProvider::Observe(
       break;
     case chrome::NOTIFICATION_EXTENSION_PROCESS_TERMINATED:
       RemoveFromTaskManager(
-          content::Details<ExtensionHost>(details).ptr()->render_view_host());
+          content::Details<extensions::ExtensionHost>(details).ptr()->
+          render_view_host());
       break;
     case chrome::NOTIFICATION_EXTENSION_VIEW_UNREGISTERED:
       RemoveFromTaskManager(
diff --git a/chrome/browser/ui/app_modal_dialogs/javascript_dialog_creator.cc b/chrome/browser/ui/app_modal_dialogs/javascript_dialog_creator.cc
index 2e542dc..069e16e 100644
--- a/chrome/browser/ui/app_modal_dialogs/javascript_dialog_creator.cc
+++ b/chrome/browser/ui/app_modal_dialogs/javascript_dialog_creator.cc
@@ -35,7 +35,8 @@ class ChromeJavaScriptDialogCreator : public JavaScriptDialogCreator,
  public:
   static ChromeJavaScriptDialogCreator* GetInstance();
 
-  explicit ChromeJavaScriptDialogCreator(ExtensionHost* extension_host);
+  explicit ChromeJavaScriptDialogCreator(
+      extensions::ExtensionHost* extension_host);
   virtual ~ChromeJavaScriptDialogCreator();
 
   virtual void RunJavaScriptDialog(
@@ -87,7 +88,7 @@ class ChromeJavaScriptDialogCreator : public JavaScriptDialogCreator,
   // Extension Host which owns the ChromeJavaScriptDialogCreator instance.
   // It's used to get a extension name from a URL.
   // If it's not owned by any Extension, it should be NULL.
-  ExtensionHost* extension_host_;
+  extensions::ExtensionHost* extension_host_;
 
   content::NotificationRegistrar registrar_;
 
@@ -106,7 +107,7 @@ ChromeJavaScriptDialogCreator::~ChromeJavaScriptDialogCreator() {
 }
 
 ChromeJavaScriptDialogCreator::ChromeJavaScriptDialogCreator(
-    ExtensionHost* extension_host)
+    extensions::ExtensionHost* extension_host)
     : extension_host_(extension_host) {
   registrar_.Add(this, chrome::NOTIFICATION_EXTENSION_HOST_DESTROYED,
                  content::Source<Profile>(extension_host_->profile()));
@@ -271,6 +272,6 @@ content::JavaScriptDialogCreator* GetJavaScriptDialogCreatorInstance() {
 }
 
 content::JavaScriptDialogCreator* CreateJavaScriptDialogCreatorInstance(
-    ExtensionHost* extension_host) {
+    extensions::ExtensionHost* extension_host) {
   return new ChromeJavaScriptDialogCreator(extension_host);
 }
diff --git a/chrome/browser/ui/app_modal_dialogs/javascript_dialog_creator.h b/chrome/browser/ui/app_modal_dialogs/javascript_dialog_creator.h
index 05bdc2b..a01de88 100644
--- a/chrome/browser/ui/app_modal_dialogs/javascript_dialog_creator.h
+++ b/chrome/browser/ui/app_modal_dialogs/javascript_dialog_creator.h
@@ -9,7 +9,9 @@ namespace content {
 class JavaScriptDialogCreator;
 }
 
+namespace extensions {
 class ExtensionHost;
+}
 
 // Returns a JavaScriptDialogCreator that creates real dialogs.
 // It returns a Singleton instance of JavaScriptDialogCreator,
@@ -19,6 +21,6 @@ content::JavaScriptDialogCreator* GetJavaScriptDialogCreatorInstance();
 // Creates and returns a JavaScriptDialogCreator owned by |extension_host|.
 // This is not the Singleton instance, so the caller must delete it.
 content::JavaScriptDialogCreator* CreateJavaScriptDialogCreatorInstance(
-    ExtensionHost* extension_host);
+    extensions::ExtensionHost* extension_host);
 
 #endif  // CHROME_BROWSER_UI_APP_MODAL_DIALOGS_JAVASCRIPT_DIALOG_CREATOR_H_
diff --git a/chrome/browser/ui/cocoa/extensions/extension_popup_controller.h b/chrome/browser/ui/cocoa/extensions/extension_popup_controller.h
index 06a4d23..782505d 100644
--- a/chrome/browser/ui/cocoa/extensions/extension_popup_controller.h
+++ b/chrome/browser/ui/cocoa/extensions/extension_popup_controller.h
@@ -16,13 +16,16 @@
 
 class Browser;
 class DevtoolsNotificationBridge;
-class ExtensionHost;
 class ExtensionPopupContainer;
 
 namespace content {
 class NotificationRegistrar;
 }
 
+namespace extensions {
+class ExtensionHost;
+}
+
 // This controller manages a single browser action popup that can appear once a
 // user has clicked on a browser action button. It instantiates the extension
 // popup view showing the content and resizes the window to accomodate any size
@@ -40,7 +43,7 @@ class NotificationRegistrar;
   NSRect extensionFrame_;
 
   // The extension host object.
-  scoped_ptr<ExtensionHost> host_;
+  scoped_ptr<extensions::ExtensionHost> host_;
 
   scoped_ptr<content::NotificationRegistrar> registrar_;
   scoped_ptr<DevtoolsNotificationBridge> notificationBridge_;
@@ -54,7 +57,7 @@ class NotificationRegistrar;
 }
 
 // Returns the ExtensionHost object associated with this popup.
-- (ExtensionHost*)extensionHost;
+- (extensions::ExtensionHost*)extensionHost;
 
 // Starts the process of showing the given popup URL. Instantiates an
 // ExtensionPopupController with the parent window retrieved from |browser|, a
diff --git a/chrome/browser/ui/cocoa/extensions/extension_popup_controller.mm b/chrome/browser/ui/cocoa/extensions/extension_popup_controller.mm
index b49a17a..158155d 100644
--- a/chrome/browser/ui/cocoa/extensions/extension_popup_controller.mm
+++ b/chrome/browser/ui/cocoa/extensions/extension_popup_controller.mm
@@ -40,7 +40,7 @@ CGFloat Clamp(CGFloat value, CGFloat min, CGFloat max) {
 @interface ExtensionPopupController (Private)
 // Callers should be using the public static method for initialization.
 // NOTE: This takes ownership of |host|.
-- (id)initWithHost:(ExtensionHost*)host
+- (id)initWithHost:(extensions::ExtensionHost*)host
       parentWindow:(NSWindow*)parentWindow
         anchoredAt:(NSPoint)anchoredAt
      arrowLocation:(info_bubble::BubbleArrowLocation)arrowLocation
@@ -87,8 +87,8 @@ class DevtoolsNotificationBridge : public content::NotificationObserver {
                const content::NotificationDetails& details) {
     switch (type) {
       case chrome::NOTIFICATION_EXTENSION_HOST_DID_STOP_LOADING: {
-        if (content::Details<ExtensionHost>([controller_ extensionHost]) ==
-                details) {
+        if (content::Details<extensions::ExtensionHost>(
+                [controller_ extensionHost]) == details) {
           [controller_ showDevTools];
         }
         break;
@@ -123,7 +123,7 @@ class DevtoolsNotificationBridge : public content::NotificationObserver {
 
 @implementation ExtensionPopupController
 
-- (id)initWithHost:(ExtensionHost*)host
+- (id)initWithHost:(extensions::ExtensionHost*)host
       parentWindow:(NSWindow*)parentWindow
         anchoredAt:(NSPoint)anchoredAt
      arrowLocation:(info_bubble::BubbleArrowLocation)arrowLocation
@@ -210,7 +210,7 @@ class DevtoolsNotificationBridge : public content::NotificationObserver {
   return [static_cast<InfoBubbleWindow*>([self window]) isClosing];
 }
 
-- (ExtensionHost*)extensionHost {
+- (extensions::ExtensionHost*)extensionHost {
   return host_.get();
 }
 
@@ -235,7 +235,7 @@ class DevtoolsNotificationBridge : public content::NotificationObserver {
   if (!manager)
     return nil;
 
-  ExtensionHost* host = manager->CreatePopupHost(url, browser);
+  extensions::ExtensionHost* host = manager->CreatePopupHost(url, browser);
   DCHECK(host);
   if (!host)
     return nil;
diff --git a/chrome/browser/ui/cocoa/extensions/extension_view_mac.h b/chrome/browser/ui/cocoa/extensions/extension_view_mac.h
index 8ba978ec..bbe08f9 100644
--- a/chrome/browser/ui/cocoa/extensions/extension_view_mac.h
+++ b/chrome/browser/ui/cocoa/extensions/extension_view_mac.h
@@ -11,13 +11,16 @@
 #include "ui/gfx/size.h"
 
 class Browser;
-class ExtensionHost;
 class SkBitmap;
 
 namespace content {
 class RenderViewHost;
 }
 
+namespace extensions {
+class ExtensionHost;
+}
+
 // This class represents extension views. An extension view internally contains
 // a bridge to an extension process, which draws to the extension view's
 // native view object through IPC.
@@ -31,7 +34,7 @@ class ExtensionViewMac {
     virtual void OnExtensionViewDidShow(ExtensionViewMac* view) {};
   };
 
-  ExtensionViewMac(ExtensionHost* extension_host, Browser* browser);
+  ExtensionViewMac(extensions::ExtensionHost* extension_host, Browser* browser);
   ~ExtensionViewMac();
 
   // Starts the extension process and creates the native view. You must call
@@ -84,7 +87,7 @@ class ExtensionViewMac {
 
   Browser* browser_;  // weak
 
-  ExtensionHost* extension_host_;  // weak
+  extensions::ExtensionHost* extension_host_;  // weak
 
   // The background the view should have once it is initialized. This is set
   // when the view has a custom background, but hasn't been initialized yet.
diff --git a/chrome/browser/ui/cocoa/extensions/extension_view_mac.mm b/chrome/browser/ui/cocoa/extensions/extension_view_mac.mm
index 3c03417..642face 100644
--- a/chrome/browser/ui/cocoa/extensions/extension_view_mac.mm
+++ b/chrome/browser/ui/cocoa/extensions/extension_view_mac.mm
@@ -19,7 +19,7 @@ const CGFloat ExtensionViewMac::kMinHeight = 25.0;
 const CGFloat ExtensionViewMac::kMaxWidth = 800.0;
 const CGFloat ExtensionViewMac::kMaxHeight = 600.0;
 
-ExtensionViewMac::ExtensionViewMac(ExtensionHost* extension_host,
+ExtensionViewMac::ExtensionViewMac(extensions::ExtensionHost* extension_host,
                                    Browser* browser)
     : browser_(browser),
       extension_host_(extension_host),
diff --git a/chrome/browser/ui/cocoa/infobars/extension_infobar_controller.mm b/chrome/browser/ui/cocoa/infobars/extension_infobar_controller.mm
index fb52ade..5d867b5 100644
--- a/chrome/browser/ui/cocoa/infobars/extension_infobar_controller.mm
+++ b/chrome/browser/ui/cocoa/infobars/extension_infobar_controller.mm
@@ -146,8 +146,8 @@ class InfobarBridge : public ExtensionInfoBarDelegate::DelegateObserver,
     dropdownButton_.reset([[MenuButton alloc] init]);
     [dropdownButton_ setOpenMenuOnClick:YES];
 
-    ExtensionHost* extensionHost = delegate_->AsExtensionInfoBarDelegate()->
-        extension_host();
+    extensions::ExtensionHost* extensionHost =
+        delegate_->AsExtensionInfoBarDelegate()->extension_host();
     Browser* browser =
         browser::FindBrowserWithWebContents(owner->web_contents());
     contextMenu_.reset([[ExtensionActionContextMenu alloc]
diff --git a/chrome/browser/ui/gtk/extensions/extension_popup_gtk.cc b/chrome/browser/ui/gtk/extensions/extension_popup_gtk.cc
index e9a1098..119705b 100644
--- a/chrome/browser/ui/gtk/extensions/extension_popup_gtk.cc
+++ b/chrome/browser/ui/gtk/extensions/extension_popup_gtk.cc
@@ -40,7 +40,7 @@ const int ExtensionPopupGtk::kMaxWidth = 800;
 const int ExtensionPopupGtk::kMaxHeight = 600;
 
 ExtensionPopupGtk::ExtensionPopupGtk(Browser* browser,
-                                     ExtensionHost* host,
+                                     extensions::ExtensionHost* host,
                                      GtkWidget* anchor,
                                      ShowAction show_action)
     : browser_(browser),
@@ -84,7 +84,7 @@ void ExtensionPopupGtk::Show(const GURL& url, Browser* browser,
   if (!manager)
     return;
 
-  ExtensionHost* host = manager->CreatePopupHost(url, browser);
+  extensions::ExtensionHost* host = manager->CreatePopupHost(url, browser);
   // This object will delete itself when the bubble is closed.
   new ExtensionPopupGtk(browser, host, anchor, show_action);
 }
@@ -94,11 +94,11 @@ void ExtensionPopupGtk::Observe(int type,
                                 const content::NotificationDetails& details) {
   switch (type) {
     case chrome::NOTIFICATION_EXTENSION_HOST_DID_STOP_LOADING:
-      if (content::Details<ExtensionHost>(host_.get()) == details)
+      if (content::Details<extensions::ExtensionHost>(host_.get()) == details)
         ShowPopup();
       break;
     case chrome::NOTIFICATION_EXTENSION_HOST_VIEW_SHOULD_CLOSE:
-      if (content::Details<ExtensionHost>(host_.get()) == details)
+      if (content::Details<extensions::ExtensionHost>(host_.get()) == details)
         DestroyPopup();
       break;
     case content::NOTIFICATION_DEVTOOLS_WINDOW_OPENING:
diff --git a/chrome/browser/ui/gtk/extensions/extension_popup_gtk.h b/chrome/browser/ui/gtk/extensions/extension_popup_gtk.h
index f6d05d1..ef1e74c 100644
--- a/chrome/browser/ui/gtk/extensions/extension_popup_gtk.h
+++ b/chrome/browser/ui/gtk/extensions/extension_popup_gtk.h
@@ -15,9 +15,12 @@
 #include "ui/gfx/rect.h"
 
 class Browser;
-class ExtensionHost;
 class GURL;
 
+namespace extensions {
+class ExtensionHost;
+}
+
 class ExtensionPopupGtk : public content::NotificationObserver,
                           public BubbleDelegateGtk,
                           public ExtensionViewGtk::Container {
@@ -68,7 +71,7 @@ class ExtensionPopupGtk : public content::NotificationObserver,
 
  private:
   ExtensionPopupGtk(Browser* browser,
-                    ExtensionHost* host,
+                    extensions::ExtensionHost* host,
                     GtkWidget* anchor,
                     ShowAction show_action);
   virtual ~ExtensionPopupGtk();
@@ -86,7 +89,7 @@ class ExtensionPopupGtk : public content::NotificationObserver,
   BubbleGtk* bubble_;
 
   // We take ownership of the popup ExtensionHost.
-  scoped_ptr<ExtensionHost> host_;
+  scoped_ptr<extensions::ExtensionHost> host_;
 
   // The widget for anchoring the position of the bubble.
   GtkWidget* anchor_;
diff --git a/chrome/browser/ui/gtk/extensions/extension_view_gtk.cc b/chrome/browser/ui/gtk/extensions/extension_view_gtk.cc
index 143d4ed..5b2cf1d 100644
--- a/chrome/browser/ui/gtk/extensions/extension_view_gtk.cc
+++ b/chrome/browser/ui/gtk/extensions/extension_view_gtk.cc
@@ -12,7 +12,7 @@
 #include "content/public/browser/web_contents.h"
 #include "content/public/browser/web_contents_view.h"
 
-ExtensionViewGtk::ExtensionViewGtk(ExtensionHost* extension_host,
+ExtensionViewGtk::ExtensionViewGtk(extensions::ExtensionHost* extension_host,
                                    Browser* browser)
     : browser_(browser),
       extension_host_(extension_host),
diff --git a/chrome/browser/ui/gtk/extensions/extension_view_gtk.h b/chrome/browser/ui/gtk/extensions/extension_view_gtk.h
index 0a3d9e9..97cdd80 100644
--- a/chrome/browser/ui/gtk/extensions/extension_view_gtk.h
+++ b/chrome/browser/ui/gtk/extensions/extension_view_gtk.h
@@ -11,16 +11,19 @@
 #include "ui/gfx/size.h"
 
 class Browser;
-class ExtensionHost;
 class SkBitmap;
 
 namespace content {
 class RenderViewHost;
 }
 
+namespace extensions {
+class ExtensionHost;
+}
+
 class ExtensionViewGtk {
  public:
-  ExtensionViewGtk(ExtensionHost* extension_host, Browser* browser);
+  ExtensionViewGtk(extensions::ExtensionHost* extension_host, Browser* browser);
 
   class Container {
    public:
@@ -54,7 +57,7 @@ class ExtensionViewGtk {
 
   Browser* browser_;
 
-  ExtensionHost* extension_host_;
+  extensions::ExtensionHost* extension_host_;
 
   // The background the view should have once it is initialized. This is set
   // when the view has a custom background, but hasn't been initialized yet.
diff --git a/chrome/browser/ui/gtk/infobars/extension_infobar_gtk.cc b/chrome/browser/ui/gtk/infobars/extension_infobar_gtk.cc
index 4ad5c21..07ae2a8 100644
--- a/chrome/browser/ui/gtk/infobars/extension_infobar_gtk.cc
+++ b/chrome/browser/ui/gtk/infobars/extension_infobar_gtk.cc
@@ -109,8 +109,8 @@ void ExtensionInfoBarGtk::BuildWidgets() {
   gtk_util::CenterWidgetInHBox(hbox_, button_, false, 0);
 
   // Start loading the image for the menu button.
-  const extensions::Extension* extension = delegate_->extension_host()->
-      extension();
+  const extensions::Extension* extension =
+      delegate_->extension_host()->extension();
   ExtensionResource icon_resource = extension->GetIconResource(
       ExtensionIconSet::EXTENSION_ICON_BITTY, ExtensionIconSet::MATCH_EXACTLY);
   // Create a tracker to load the image. It will report back on OnImageLoaded.
@@ -124,7 +124,7 @@ void ExtensionInfoBarGtk::BuildWidgets() {
   gtk_alignment_set_padding(GTK_ALIGNMENT(alignment_), 0, 1, 0, 0);
   gtk_box_pack_start(GTK_BOX(hbox_), alignment_, TRUE, TRUE, 0);
 
-  ExtensionHost* extension_host = delegate_->extension_host();
+  extensions::ExtensionHost* extension_host = delegate_->extension_host();
   view_ = extension_host->view();
 
   if (gtk_widget_get_parent(view_->native_view())) {
diff --git a/chrome/browser/ui/views/extensions/extension_dialog.cc b/chrome/browser/ui/views/extensions/extension_dialog.cc
index dec0bfa..b73427b 100644
--- a/chrome/browser/ui/views/extensions/extension_dialog.cc
+++ b/chrome/browser/ui/views/extensions/extension_dialog.cc
@@ -27,7 +27,7 @@
 
 using content::WebContents;
 
-ExtensionDialog::ExtensionDialog(ExtensionHost* host,
+ExtensionDialog::ExtensionDialog(extensions::ExtensionHost* host,
                                  ExtensionDialogObserver* observer)
     : window_(NULL),
       extension_host_(host),
@@ -57,7 +57,7 @@ ExtensionDialog* ExtensionDialog::Show(
     int height,
     const string16& title,
     ExtensionDialogObserver* observer) {
-  ExtensionHost* host = CreateExtensionHost(url, profile);
+  extensions::ExtensionHost* host = CreateExtensionHost(url, profile);
   if (!host)
     return NULL;
   host->SetAssociatedWebContents(web_contents);
@@ -73,7 +73,7 @@ ExtensionDialog* ExtensionDialog::ShowFullscreen(
     Profile* profile,
     const string16& title,
     ExtensionDialogObserver* observer) {
-  ExtensionHost* host = CreateExtensionHost(url, profile);
+  extensions::ExtensionHost* host = CreateExtensionHost(url, profile);
   if (!host)
     return NULL;
 
@@ -83,9 +83,10 @@ ExtensionDialog* ExtensionDialog::ShowFullscreen(
 #endif
 
 // static
-ExtensionDialog* ExtensionDialog::ShowInternal(const GURL& url,
+ExtensionDialog* ExtensionDialog::ShowInternal(
+    const GURL& url,
     BaseWindow* base_window,
-    ExtensionHost* host,
+    extensions::ExtensionHost* host,
     int width,
     int height,
     bool fullscreen,
@@ -112,8 +113,9 @@ ExtensionDialog* ExtensionDialog::ShowInternal(const GURL& url,
 }
 
 // static
-ExtensionHost* ExtensionDialog::CreateExtensionHost(const GURL& url,
-                                                    Profile* profile) {
+extensions::ExtensionHost* ExtensionDialog::CreateExtensionHost(
+    const GURL& url,
+    Profile* profile) {
   DCHECK(profile);
   ExtensionProcessManager* manager = profile->GetExtensionProcessManager();
 
@@ -263,17 +265,17 @@ void ExtensionDialog::Observe(int type,
       extension_host_->view()->set_background(NULL);
       // The render view is created during the LoadURL(), so we should
       // set the focus to the view if nobody else takes the focus.
-      if (content::Details<ExtensionHost>(host()) == details)
+      if (content::Details<extensions::ExtensionHost>(host()) == details)
         MaybeFocusRenderView();
       break;
     case chrome::NOTIFICATION_EXTENSION_HOST_VIEW_SHOULD_CLOSE:
       // If we aren't the host of the popup, then disregard the notification.
-      if (content::Details<ExtensionHost>(host()) != details)
+      if (content::Details<extensions::ExtensionHost>(host()) != details)
         return;
       Close();
       break;
     case chrome::NOTIFICATION_EXTENSION_PROCESS_TERMINATED:
-      if (content::Details<ExtensionHost>(host()) != details)
+      if (content::Details<extensions::ExtensionHost>(host()) != details)
         return;
       if (observer_)
         observer_->ExtensionTerminated(this);
diff --git a/chrome/browser/ui/views/extensions/extension_dialog.h b/chrome/browser/ui/views/extensions/extension_dialog.h
index e52485c..882747d 100644
--- a/chrome/browser/ui/views/extensions/extension_dialog.h
+++ b/chrome/browser/ui/views/extensions/extension_dialog.h
@@ -13,7 +13,6 @@
 
 class BaseWindow;
 class ExtensionDialogObserver;
-class ExtensionHost;
 class GURL;
 class Profile;
 
@@ -21,6 +20,10 @@ namespace content {
 class WebContents;
 }
 
+namespace extensions {
+class ExtensionHost;
+}
+
 // Modal dialog containing contents provided by an extension.
 // Dialog is automatically centered in the owning window and has fixed size.
 // For example, used by the Chrome OS file browser.
@@ -76,7 +79,7 @@ class ExtensionDialog : public views::WidgetDelegate,
   // Sets minimum contents size in pixels and makes the window resizable.
   void SetMinimumContentsSize(int width, int height);
 
-  ExtensionHost* host() const { return extension_host_.get(); }
+  extensions::ExtensionHost* host() const { return extension_host_.get(); }
 
   // views::WidgetDelegate overrides.
   virtual bool CanResize() const OVERRIDE;
@@ -101,19 +104,20 @@ class ExtensionDialog : public views::WidgetDelegate,
   friend class base::RefCounted<ExtensionDialog>;
 
   // Use Show() to create instances.
-  ExtensionDialog(ExtensionHost* host, ExtensionDialogObserver* observer);
+  ExtensionDialog(extensions::ExtensionHost* host,
+                  ExtensionDialogObserver* observer);
 
   static ExtensionDialog* ShowInternal(const GURL& url,
                                        BaseWindow* base_window,
-                                       ExtensionHost* host,
+                                       extensions::ExtensionHost* host,
                                        int width,
                                        int height,
                                        bool fullscreen,
                                        const string16& title,
                                        ExtensionDialogObserver* observer);
 
-  static ExtensionHost* CreateExtensionHost(const GURL& url,
-                                            Profile* profile);
+  static extensions::ExtensionHost* CreateExtensionHost(const GURL& url,
+                                                        Profile* profile);
 
   void InitWindow(BaseWindow* base_window, int width, int height);
   void InitWindowFullscreen();
@@ -125,7 +129,7 @@ class ExtensionDialog : public views::WidgetDelegate,
   string16 window_title_;
 
   // The contained host for the view.
-  scoped_ptr<ExtensionHost> extension_host_;
+  scoped_ptr<extensions::ExtensionHost> extension_host_;
 
   content::NotificationRegistrar registrar_;
 
diff --git a/chrome/browser/ui/views/extensions/extension_popup.cc b/chrome/browser/ui/views/extensions/extension_popup.cc
index ec3fc71..68d6925 100644
--- a/chrome/browser/ui/views/extensions/extension_popup.cc
+++ b/chrome/browser/ui/views/extensions/extension_popup.cc
@@ -62,7 +62,7 @@ const int ExtensionPopup::kMaxHeight = 600;
 
 ExtensionPopup::ExtensionPopup(
     Browser* browser,
-    ExtensionHost* host,
+    extensions::ExtensionHost* host,
     views::View* anchor_view,
     views::BubbleBorder::ArrowLocation arrow_location)
     : BubbleDelegateView(anchor_view, arrow_location),
@@ -114,7 +114,7 @@ void ExtensionPopup::Observe(int type,
       break;
     case chrome::NOTIFICATION_EXTENSION_HOST_VIEW_SHOULD_CLOSE:
       // If we aren't the host of the popup, then disregard the notification.
-      if (content::Details<ExtensionHost>(host()) == details)
+      if (content::Details<extensions::ExtensionHost>(host()) == details)
         GetWidget()->Close();
       break;
     case content::NOTIFICATION_DEVTOOLS_WINDOW_CLOSING:
@@ -178,7 +178,7 @@ ExtensionPopup* ExtensionPopup::ShowPopup(
     views::BubbleBorder::ArrowLocation arrow_location) {
   ExtensionProcessManager* manager =
       browser->profile()->GetExtensionProcessManager();
-  ExtensionHost* host = manager->CreatePopupHost(url, browser);
+  extensions::ExtensionHost* host = manager->CreatePopupHost(url, browser);
   ExtensionPopup* popup = new ExtensionPopup(browser, host, anchor_view,
       arrow_location);
   views::BubbleDelegateView::CreateBubble(popup);
diff --git a/chrome/browser/ui/views/extensions/extension_popup.h b/chrome/browser/ui/views/extensions/extension_popup.h
index dd22fcd..bdd5147f 100644
--- a/chrome/browser/ui/views/extensions/extension_popup.h
+++ b/chrome/browser/ui/views/extensions/extension_popup.h
@@ -38,7 +38,7 @@ class ExtensionPopup : public views::BubbleDelegateView,
       views::View* anchor_view,
       views::BubbleBorder::ArrowLocation arrow_location);
 
-  ExtensionHost* host() const { return extension_host_.get(); }
+  extensions::ExtensionHost* host() const { return extension_host_.get(); }
 
   // content::NotificationObserver overrides.
   virtual void Observe(int type,
@@ -63,7 +63,7 @@ class ExtensionPopup : public views::BubbleDelegateView,
 
  private:
   ExtensionPopup(Browser* browser,
-                 ExtensionHost* host,
+                 extensions::ExtensionHost* host,
                  views::View* anchor_view,
                  views::BubbleBorder::ArrowLocation arrow_location);
 
@@ -73,7 +73,7 @@ class ExtensionPopup : public views::BubbleDelegateView,
   void CloseBubble();
 
   // The contained host for the view.
-  scoped_ptr<ExtensionHost> extension_host_;
+  scoped_ptr<extensions::ExtensionHost> extension_host_;
 
   // Flag used to indicate if the pop-up should open a devtools window once
   // it is shown inspecting it.
diff --git a/chrome/browser/ui/views/extensions/extension_view.cc b/chrome/browser/ui/views/extensions/extension_view.cc
index f1a43c5..18023b4 100644
--- a/chrome/browser/ui/views/extensions/extension_view.cc
+++ b/chrome/browser/ui/views/extensions/extension_view.cc
@@ -14,7 +14,7 @@
 #include "content/public/browser/web_contents_view.h"
 #include "ui/views/widget/widget.h"
 
-ExtensionView::ExtensionView(ExtensionHost* host, Browser* browser)
+ExtensionView::ExtensionView(extensions::ExtensionHost* host, Browser* browser)
     : host_(host),
       browser_(browser),
       initialized_(false),
diff --git a/chrome/browser/ui/views/extensions/extension_view.h b/chrome/browser/ui/views/extensions/extension_view.h
index 09b0e98..926ddae1 100644
--- a/chrome/browser/ui/views/extensions/extension_view.h
+++ b/chrome/browser/ui/views/extensions/extension_view.h
@@ -11,11 +11,11 @@
 #include "ui/views/controls/native/native_view_host.h"
 
 class Browser;
-class ExtensionHost;
 class ExtensionView;
 
 namespace extensions {
 class Extension;
+class ExtensionHost;
 }
 
 namespace content {
@@ -25,7 +25,7 @@ class RenderViewHost;
 // This handles the display portion of an ExtensionHost.
 class ExtensionView : public views::NativeViewHost {
  public:
-  ExtensionView(ExtensionHost* host, Browser* browser);
+  ExtensionView(extensions::ExtensionHost* host, Browser* browser);
   virtual ~ExtensionView();
 
   // A class that represents the container that this view is in.
@@ -37,7 +37,7 @@ class ExtensionView : public views::NativeViewHost {
     virtual void OnViewWasResized() {}
   };
 
-  ExtensionHost* host() const { return host_; }
+  extensions::ExtensionHost* host() const { return host_; }
   Browser* browser() const { return browser_; }
   const extensions::Extension* extension() const;
   content::RenderViewHost* render_view_host() const;
@@ -70,7 +70,7 @@ class ExtensionView : public views::NativeViewHost {
   virtual void OnBoundsChanged(const gfx::Rect& previous_bounds) OVERRIDE;
 
  private:
-  friend class ExtensionHost;
+  friend class extensions::ExtensionHost;
 
   // Initializes the RenderWidgetHostView for this object.
   void CreateWidgetHostView();
@@ -84,7 +84,7 @@ class ExtensionView : public views::NativeViewHost {
 
   // The running extension instance that we're displaying.
   // Note that host_ owns view
-  ExtensionHost* host_;
+  extensions::ExtensionHost* host_;
 
   // The browser window that this view is in.
   Browser* browser_;
diff --git a/chrome/browser/ui/views/infobars/extension_infobar.cc b/chrome/browser/ui/views/infobars/extension_infobar.cc
index abe8fcd..e56fbbc 100644
--- a/chrome/browser/ui/views/infobars/extension_infobar.cc
+++ b/chrome/browser/ui/views/infobars/extension_infobar.cc
@@ -118,7 +118,7 @@ void ExtensionInfoBar::ViewHierarchyChanged(bool is_add,
   menu_->set_focusable(true);
   AddChildView(menu_);
 
-  ExtensionHost* extension_host = GetDelegate()->extension_host();
+  extensions::ExtensionHost* extension_host = GetDelegate()->extension_host();
   AddChildView(extension_host->view());
 
   // This must happen after adding all other children so InfoBarView can ensure
diff --git a/chrome/browser/ui/webui/extensions/extension_settings_handler.cc b/chrome/browser/ui/webui/extensions/extension_settings_handler.cc
index 2d69e74..c1ffe64 100644
--- a/chrome/browser/ui/webui/extensions/extension_settings_handler.cc
+++ b/chrome/browser/ui/webui/extensions/extension_settings_handler.cc
@@ -571,7 +571,8 @@ void ExtensionSettingsHandler::HandleInspectMessage(const ListValue* args) {
     extensions::LazyBackgroundTaskQueue* queue =
         extensions::ExtensionSystem::Get(profile)->lazy_background_task_queue();
 
-    ExtensionHost* host = pm->GetBackgroundHostForExtension(extension->id());
+    extensions::ExtensionHost* host =
+        pm->GetBackgroundHostForExtension(extension->id());
     if (host) {
       InspectExtensionHost(host);
     } else {
@@ -880,7 +881,8 @@ ExtensionSettingsHandler::GetExtensionUninstallDialog() {
 #endif  // !defined(OS_ANDROID)
 }
 
-void ExtensionSettingsHandler::InspectExtensionHost(ExtensionHost* host) {
+void ExtensionSettingsHandler::InspectExtensionHost(
+    extensions::ExtensionHost* host) {
   if (host)
     DevToolsWindow::OpenDevToolsWindow(host->render_view_host());
 }
diff --git a/chrome/browser/ui/webui/extensions/extension_settings_handler.h b/chrome/browser/ui/webui/extensions/extension_settings_handler.h
index 99f0488..bbe504d 100644
--- a/chrome/browser/ui/webui/extensions/extension_settings_handler.h
+++ b/chrome/browser/ui/webui/extensions/extension_settings_handler.h
@@ -24,7 +24,6 @@
 #include "googleurl/src/gurl.h"
 #include "ui/base/dialogs/select_file_dialog.h"
 
-class ExtensionHost;
 class ExtensionService;
 class FilePath;
 class PrefService;
@@ -36,6 +35,7 @@ class ListValue;
 
 namespace extensions {
 class Extension;
+class ExtensionHost;
 class ManagementPolicy;
 }
 
@@ -173,7 +173,7 @@ class ExtensionSettingsHandler : public content::WebUIMessageHandler,
   ExtensionUninstallDialog* GetExtensionUninstallDialog();
 
   // Helper to inspect an ExtensionHost after it has been loaded.
-  void InspectExtensionHost(ExtensionHost* host);
+  void InspectExtensionHost(extensions::ExtensionHost* host);
 
   // Our model.  Outlives us since it's owned by our containing profile.
   ExtensionService* extension_service_;