Move StoragePartition into content/public and remove BrowserContext::GetDOMStorageContext().

Eventually all the storage context accessors will be removed from BrowserContext. Instead, users should retrieve the storage context from the StoragePartition.

This also changes RenderProcessHost to take in a StoragePartition removing the need for a re-lookup its storage contexts.

BUG=85121,143486

Review URL: https://chromiumcodereview.appspot.com/10837230

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@152251 0039d316-1c4b-4281-b951-d872f2087c98

20 files changed, 366 insertions, 286 deletions

diff --git a/content/browser/browser_context.cc b/content/browser/browser_context.cc
index 15735c9..527fe43 100644
--- a/content/browser/browser_context.cc
+++ b/content/browser/browser_context.cc
@@ -11,8 +11,8 @@
 #include "content/browser/in_process_webkit/indexed_db_context_impl.h"
 #include "content/browser/renderer_host/resource_dispatcher_host_impl.h"
 #include "content/public/browser/resource_context.h"
-#include "content/browser/storage_partition.h"
-#include "content/browser/storage_partition_map.h"
+#include "content/browser/storage_partition_impl.h"
+#include "content/browser/storage_partition_impl_map.h"
 #include "content/common/child_process_host_impl.h"
 #include "content/public/browser/browser_thread.h"
 #include "content/public/browser/content_browser_client.h"
@@ -35,53 +35,22 @@ namespace {
 StoragePartition* GetStoragePartitionByPartitionId(
     BrowserContext* browser_context,
     const std::string& partition_id) {
-  StoragePartitionMap* partition_map = static_cast<StoragePartitionMap*>(
-      browser_context->GetUserData(kStorageParitionMapKeyName));
+  StoragePartitionImplMap* partition_map =
+      static_cast<StoragePartitionImplMap*>(
+          browser_context->GetUserData(kStorageParitionMapKeyName));
   if (!partition_map) {
-    partition_map = new StoragePartitionMap(browser_context);
+    partition_map = new StoragePartitionImplMap(browser_context);
     browser_context->SetUserData(kStorageParitionMapKeyName, partition_map);
   }
 
   return partition_map->Get(partition_id);
 }
 
-StoragePartition* GetStoragePartition(BrowserContext* browser_context,
-                                      int renderer_child_id) {
-  const std::string& partition_id =
-      GetContentClient()->browser()->GetStoragePartitionIdForChildProcess(
-          browser_context,
-          renderer_child_id);
-
-  return GetStoragePartitionByPartitionId(browser_context, partition_id);
-}
-
-// Run |callback| on each storage partition in |browser_context|.
-void ForEachStoragePartition(
-    BrowserContext* browser_context,
-    const base::Callback<void(StoragePartition*)>& callback) {
-  StoragePartitionMap* partition_map = static_cast<StoragePartitionMap*>(
-      browser_context->GetUserData(kStorageParitionMapKeyName));
-  if (!partition_map) {
-    return;
-  }
-
-  partition_map->ForEach(callback);
-}
-
-// Used to convert a callback meant to take a DOMStorageContextImpl* into one
-// that can take a StoragePartition*.
-void ProcessDOMStorageContext(
-    const base::Callback<void(DOMStorageContextImpl*)>& callback,
-    StoragePartition* partition) {
-  callback.Run(partition->dom_storage_context());
-}
-
 // Run |callback| on each DOMStorageContextImpl in |browser_context|.
-void ForEachDOMStorageContext(
-      BrowserContext* browser_context,
-      const base::Callback<void(DOMStorageContextImpl*)>& callback) {
-  ForEachStoragePartition(browser_context,
-                          base::Bind(&ProcessDOMStorageContext, callback));
+void PurgeDOMStorageContextInPartition(const std::string& id,
+                                       StoragePartition* storage_partition) {
+  static_cast<StoragePartitionImpl*>(storage_partition)->
+      GetDOMStorageContext()->PurgeMemory();
 }
 
 void SaveSessionStateOnIOThread(ResourceContext* resource_context) {
@@ -102,12 +71,6 @@ void PurgeMemoryOnIOThread(ResourceContext* resource_context) {
   ResourceContext::GetAppCacheService(resource_context)->PurgeMemory();
 }
 
-DOMStorageContextImpl* GetDefaultDOMStorageContextImpl(
-    BrowserContext* context) {
-  return static_cast<DOMStorageContextImpl*>(
-      BrowserContext::GetDefaultDOMStorageContext(context));
-}
-
 }  // namespace
 
 DownloadManager* BrowserContext::GetDownloadManager(
@@ -134,87 +97,82 @@ DownloadManager* BrowserContext::GetDownloadManager(
 
 quota::QuotaManager* BrowserContext::GetQuotaManager(
     BrowserContext* browser_context) {
-  // TODO(ajwong): Change this API to require a process id instead of using
-  // kInvalidChildProcessId.
-  StoragePartition* partition =
-      GetStoragePartition(browser_context,
-                          ChildProcessHostImpl::kInvalidChildProcessId);
-  return partition->quota_manager();
+  // TODO(ajwong): Change this API to require a SiteInstance instead of
+  // using GetDefaultStoragePartition().
+  return GetDefaultStoragePartition(browser_context)->GetQuotaManager();
 }
 
-DOMStorageContext* BrowserContext::GetDefaultDOMStorageContext(
+IndexedDBContext* BrowserContext::GetIndexedDBContext(
     BrowserContext* browser_context) {
-  // TODO(ajwong): Force all users to know which process id they are performing
-  // actions on behalf of, migrate them to GetDOMStorageContext(), and then
-  // delete this function.
-  return GetDOMStorageContext(browser_context,
-                              ChildProcessHostImpl::kInvalidChildProcessId);
+  // TODO(ajwong): Change this API to require a SiteInstance instead of
+  // using GetDefaultStoragePartition().
+  return GetDefaultStoragePartition(browser_context)->GetIndexedDBContext();
 }
 
-DOMStorageContext* BrowserContext::GetDOMStorageContext(
-    BrowserContext* browser_context,
-    int render_child_id) {
-  StoragePartition* partition =
-      GetStoragePartition(browser_context, render_child_id);
-  return partition->dom_storage_context();
+webkit_database::DatabaseTracker* BrowserContext::GetDatabaseTracker(
+    BrowserContext* browser_context) {
+  // TODO(ajwong): Change this API to require a SiteInstance instead of
+  // using GetDefaultStoragePartition().
+  return GetDefaultStoragePartition(browser_context)->GetDatabaseTracker();
 }
 
-DOMStorageContext* BrowserContext::GetDOMStorageContextByPartitionId(
-    BrowserContext* browser_context,
-    const std::string& partition_id) {
-  StoragePartition* partition =
-      GetStoragePartitionByPartitionId(browser_context, partition_id);
-  return partition->dom_storage_context();
+appcache::AppCacheService* BrowserContext::GetAppCacheService(
+    BrowserContext* browser_context) {
+  // TODO(ajwong): Change this API to require a SiteInstance instead of
+  // using GetDefaultStoragePartition().
+  return GetDefaultStoragePartition(browser_context)->GetAppCacheService();
 }
 
-IndexedDBContext* BrowserContext::GetIndexedDBContext(
+fileapi::FileSystemContext* BrowserContext::GetFileSystemContext(
     BrowserContext* browser_context) {
-  // TODO(ajwong): Change this API to require a process id instead of using
-  // kInvalidChildProcessId.
-  StoragePartition* partition =
-      GetStoragePartition(browser_context,
-                          ChildProcessHostImpl::kInvalidChildProcessId);
-  return partition->indexed_db_context();
+  // TODO(ajwong): Change this API to require a SiteInstance instead of
+  // using GetDefaultStoragePartition().
+  return GetDefaultStoragePartition(browser_context)->GetFileSystemContext();
 }
 
-webkit_database::DatabaseTracker* BrowserContext::GetDatabaseTracker(
-    BrowserContext* browser_context) {
-  // TODO(ajwong): Change this API to require a process id instead of using
-  // kInvalidChildProcessId.
-  StoragePartition* partition =
-      GetStoragePartition(browser_context,
-                          ChildProcessHostImpl::kInvalidChildProcessId);
-  return partition->database_tracker();
+StoragePartition* BrowserContext::GetStoragePartition(
+    BrowserContext* browser_context,
+    SiteInstance* site_instance) {
+  std::string partition_id;  // Default to "" for NULL |site_instance|.
+
+  // TODO(ajwong): After GetDefaultStoragePartition() is removed, get rid of
+  // this conditional and require that |site_instance| is non-NULL.
+  if (site_instance) {
+    partition_id = GetContentClient()->browser()->
+        GetStoragePartitionIdForSiteInstance(browser_context,
+                                             site_instance);
+  }
+
+  return GetStoragePartitionByPartitionId(browser_context, partition_id);
 }
 
-appcache::AppCacheService* BrowserContext::GetAppCacheService(
-    BrowserContext* browser_context) {
-  // TODO(ajwong): Change this API to require a process id instead of using
-  // kInvalidChildProcessId.
-  StoragePartition* partition =
-      GetStoragePartition(browser_context,
-                          ChildProcessHostImpl::kInvalidChildProcessId);
-  return partition->appcache_service();
+void BrowserContext::ForEachStoragePartition(
+    BrowserContext* browser_context,
+    const StoragePartitionCallback& callback) {
+  StoragePartitionImplMap* partition_map =
+      static_cast<StoragePartitionImplMap*>(
+          browser_context->GetUserData(kStorageParitionMapKeyName));
+  if (!partition_map)
+    return;
+
+  partition_map->ForEach(callback);
 }
 
-fileapi::FileSystemContext* BrowserContext::GetFileSystemContext(
+StoragePartition* BrowserContext::GetDefaultStoragePartition(
     BrowserContext* browser_context) {
-  // TODO(ajwong): Change this API to require a process id instead of using
-  // kInvalidChildProcessId.
-  StoragePartition* partition =
-      GetStoragePartition(browser_context,
-                          ChildProcessHostImpl::kInvalidChildProcessId);
-  return partition->filesystem_context();
+  return GetStoragePartition(browser_context, NULL);
 }
 
 void BrowserContext::EnsureResourceContextInitialized(BrowserContext* context) {
   // This will be enough to tickle initialization of BrowserContext if
   // necessary, which initializes ResourceContext. The reason we don't call
-  // ResourceContext::InitializeResourceContext directly here is that if
-  // ResourceContext ends up initializing it will call back into BrowserContext
-  // and when that call returns it'll end rewriting its UserData map (with the
-  // same value) but this causes a race condition. See http://crbug.com/115678.
-  GetStoragePartition(context, ChildProcessHostImpl::kInvalidChildProcessId);
+  // ResourceContext::InitializeResourceContext() directly here is that
+  // ResourceContext initialization may call back into BrowserContext
+  // and when that call returns it'll end rewriting its UserData map. It will
+  // end up rewriting the same value but this still causes a race condition.
+  //
+  // See http://crbug.com/115678.
+  GetDefaultStoragePartition(context);
 }
 
 void BrowserContext::SaveSessionState(BrowserContext* browser_context) {
@@ -227,10 +185,10 @@ void BrowserContext::SaveSessionState(BrowserContext* browser_context) {
                    browser_context->GetResourceContext()));
   }
 
-  // TODO(ajwong): This is the only usage of GetDefaultDOMStorageContextImpl().
-  // After we migrate this to support multiple DOMStorageContexts, don't forget
-  // to remove the GetDefaultDOMStorageContextImpl() function as well.
-  GetDefaultDOMStorageContextImpl(browser_context)->SetForceKeepSessionState();
+  DOMStorageContextImpl* dom_storage_context_impl =
+      static_cast<DOMStorageContextImpl*>(
+          GetDefaultStoragePartition(browser_context)->GetDOMStorageContext());
+  dom_storage_context_impl->SetForceKeepSessionState();
 
   if (BrowserThread::IsMessageLoopValid(BrowserThread::WEBKIT_DEPRECATED)) {
     IndexedDBContextImpl* indexed_db = static_cast<IndexedDBContextImpl*>(
@@ -250,8 +208,8 @@ void BrowserContext::PurgeMemory(BrowserContext* browser_context) {
                    browser_context->GetResourceContext()));
   }
 
-  ForEachDOMStorageContext(browser_context,
-                           base::Bind(&DOMStorageContextImpl::PurgeMemory));
+  ForEachStoragePartition(browser_context,
+                          base::Bind(&PurgeDOMStorageContextInPartition));
 }
 
 BrowserContext::~BrowserContext() {
diff --git a/content/browser/renderer_host/render_message_filter.cc b/content/browser/renderer_host/render_message_filter.cc
index 55c37e9..11738b2 100644
--- a/content/browser/renderer_host/render_message_filter.cc
+++ b/content/browser/renderer_host/render_message_filter.cc
@@ -276,7 +276,8 @@ RenderMessageFilter::RenderMessageFilter(
     BrowserContext* browser_context,
     net::URLRequestContextGetter* request_context,
     RenderWidgetHelper* render_widget_helper,
-    MediaObserver* media_observer)
+    MediaObserver* media_observer,
+    DOMStorageContextImpl* dom_storage_context)
     : resource_dispatcher_host_(ResourceDispatcherHostImpl::Get()),
       plugin_service_(plugin_service),
       profile_data_directory_(browser_context->GetPath()),
@@ -284,9 +285,7 @@ RenderMessageFilter::RenderMessageFilter(
       resource_context_(browser_context->GetResourceContext()),
       render_widget_helper_(render_widget_helper),
       incognito_(browser_context->IsOffTheRecord()),
-      dom_storage_context_(static_cast<DOMStorageContextImpl*>(
-          BrowserContext::GetDOMStorageContext(browser_context,
-                                               render_process_id))),
+      dom_storage_context_(dom_storage_context),
       render_process_id_(render_process_id),
       cpu_usage_(0),
       media_observer_(media_observer) {
diff --git a/content/browser/renderer_host/render_message_filter.h b/content/browser/renderer_host/render_message_filter.h
index 10d2b92..0ab0135 100644
--- a/content/browser/renderer_host/render_message_filter.h
+++ b/content/browser/renderer_host/render_message_filter.h
@@ -78,7 +78,8 @@ class RenderMessageFilter : public BrowserMessageFilter {
                       BrowserContext* browser_context,
                       net::URLRequestContextGetter* request_context,
                       RenderWidgetHelper* render_widget_helper,
-                      MediaObserver* media_observer);
+                      MediaObserver* media_observer,
+                      DOMStorageContextImpl* dom_storage_context);
 
   // IPC::ChannelProxy::MessageFilter methods:
   virtual void OnChannelClosing() OVERRIDE;
diff --git a/content/browser/renderer_host/render_process_host_impl.cc b/content/browser/renderer_host/render_process_host_impl.cc
index 77a9d61..69ba4f5 100644
--- a/content/browser/renderer_host/render_process_host_impl.cc
+++ b/content/browser/renderer_host/render_process_host_impl.cc
@@ -81,6 +81,7 @@
 #include "content/browser/renderer_host/socket_stream_dispatcher_host.h"
 #include "content/browser/renderer_host/text_input_client_message_filter.h"
 #include "content/browser/resolve_proxy_msg_helper.h"
+#include "content/browser/storage_partition_impl.h"
 #include "content/browser/speech/input_tag_speech_dispatcher_host.h"
 #include "content/browser/speech/speech_recognition_dispatcher_host.h"
 #include "content/browser/trace_message_filter.h"
@@ -321,7 +322,9 @@ void RenderProcessHost::SetMaxRendererProcessCount(size_t count) {
 }
 
 RenderProcessHostImpl::RenderProcessHostImpl(
-    BrowserContext* browser_context, bool is_guest)
+    BrowserContext* browser_context,
+    StoragePartitionImpl* storage_partition_impl,
+    bool is_guest)
         : fast_shutdown_started_(false),
           deleting_soon_(false),
           pending_views_(0),
@@ -333,6 +336,7 @@ RenderProcessHostImpl::RenderProcessHostImpl(
           is_initialized_(false),
           id_(ChildProcessHostImpl::GenerateChildProcessUniqueId()),
           browser_context_(browser_context),
+          storage_partition_impl_(storage_partition_impl),
           sudden_termination_allowed_(true),
           ignore_input_events_(false),
           is_guest_(is_guest) {
@@ -512,7 +516,8 @@ void RenderProcessHostImpl::CreateMessageFilters() {
           GetBrowserContext(),
           GetBrowserContext()->GetRequestContextForRenderProcess(GetID()),
           widget_helper_,
-          media_observer));
+          media_observer,
+          storage_partition_impl_->GetDOMStorageContext()));
   channel_->AddFilter(render_message_filter);
   BrowserContext* browser_context = GetBrowserContext();
   ResourceContext* resource_context = browser_context->GetResourceContext();
@@ -534,9 +539,10 @@ void RenderProcessHostImpl::CreateMessageFilters() {
           BrowserContext::GetAppCacheService(browser_context)),
       GetID()));
   channel_->AddFilter(new ClipboardMessageFilter());
-  channel_->AddFilter(new DOMStorageMessageFilter(GetID(),
-      static_cast<DOMStorageContextImpl*>(
-          BrowserContext::GetDOMStorageContext(browser_context, GetID()))));
+  channel_->AddFilter(
+      new DOMStorageMessageFilter(
+          GetID(),
+          storage_partition_impl_->GetDOMStorageContext()));
   channel_->AddFilter(new IndexedDBDispatcherHost(GetID(),
       static_cast<IndexedDBContextImpl*>(
           BrowserContext::GetIndexedDBContext(browser_context))));
@@ -596,7 +602,7 @@ void RenderProcessHostImpl::CreateMessageFilters() {
       browser_context->GetRequestContextForRenderProcess(GetID())));
   channel_->AddFilter(new QuotaDispatcherHost(
       GetID(),
-      BrowserContext::GetQuotaManager(browser_context),
+      storage_partition_impl_->GetQuotaManager(),
       GetContentClient()->browser()->CreateQuotaPermissionContext()));
   channel_->AddFilter(new GamepadBrowserMessageFilter(this));
   channel_->AddFilter(new ProfilerMessageFilter(PROCESS_TYPE_RENDERER));
diff --git a/content/browser/renderer_host/render_process_host_impl.h b/content/browser/renderer_host/render_process_host_impl.h
index 1d568ad..3876b8a 100644
--- a/content/browser/renderer_host/render_process_host_impl.h
+++ b/content/browser/renderer_host/render_process_host_impl.h
@@ -26,6 +26,7 @@ class RendererMainThread;
 class RenderWidgetHelper;
 class RenderWidgetHost;
 class RenderWidgetHostImpl;
+class StoragePartitionImpl;
 
 // Implements a concrete RenderProcessHost for the browser process for talking
 // to actual renderer processes (as opposed to mocks).
@@ -41,11 +42,18 @@ class RenderWidgetHostImpl;
 // keeps a list of RenderView (renderer) and WebContentsImpl (browser) which
 // are correlated with IDs. This way, the Views and the corresponding ViewHosts
 // communicate through the two process objects.
+//
+// A RenderProcessHost is also associated with one and only one
+// StoragePartition.  This allows us to implement strong storage isolation
+// because all the IPCs from the RenderViews (renderer) will only ever be able
+// to access the partition they are assigned to.
 class CONTENT_EXPORT RenderProcessHostImpl
     : public RenderProcessHost,
       public ChildProcessLauncher::Client {
  public:
-  RenderProcessHostImpl(BrowserContext* browser_context, bool is_guest);
+  RenderProcessHostImpl(BrowserContext* browser_context,
+                        StoragePartitionImpl* storage_partition_impl,
+                        bool is_guest);
   virtual ~RenderProcessHostImpl();
 
   // RenderProcessHost implementation (public portion).
@@ -259,6 +267,9 @@ class CONTENT_EXPORT RenderProcessHostImpl
 
   BrowserContext* browser_context_;
 
+  // Owned by |browser_context_|.
+  StoragePartitionImpl* storage_partition_impl_;
+
   // True if the process can be shut down suddenly.  If this is true, then we're
   // sure that all the RenderViews in the process can be shutdown suddenly.  If
   // it's false, then specific RenderViews might still be allowed to be shutdown
diff --git a/content/browser/renderer_host/test_render_view_host.cc b/content/browser/renderer_host/test_render_view_host.cc
index 53564b3..58796ea 100644
--- a/content/browser/renderer_host/test_render_view_host.cc
+++ b/content/browser/renderer_host/test_render_view_host.cc
@@ -12,6 +12,7 @@
 #include "content/common/view_messages.h"
 #include "content/public/browser/browser_context.h"
 #include "content/public/browser/navigation_controller.h"
+#include "content/public/browser/storage_partition.h"
 #include "content/public/common/content_client.h"
 #include "ui/gfx/rect.h"
 #include "webkit/dom_storage/dom_storage_types.h"
@@ -31,8 +32,8 @@ SessionStorageNamespaceImpl* CreateSessionStorageNamespace(
     SiteInstance* instance) {
   RenderProcessHost* process_host = instance->GetProcess();
   DOMStorageContext* dom_storage_context =
-      BrowserContext::GetDOMStorageContext(process_host->GetBrowserContext(),
-                                           process_host->GetID());
+      BrowserContext::GetStoragePartition(process_host->GetBrowserContext(),
+                                          instance)->GetDOMStorageContext();
   return new SessionStorageNamespaceImpl(
       static_cast<DOMStorageContextImpl*>(dom_storage_context));
 }
diff --git a/content/browser/site_instance_impl.cc b/content/browser/site_instance_impl.cc
index bded902..d8fcd0e 100644
--- a/content/browser/site_instance_impl.cc
+++ b/content/browser/site_instance_impl.cc
@@ -8,6 +8,7 @@
 #include "content/browser/browsing_instance.h"
 #include "content/browser/child_process_security_policy_impl.h"
 #include "content/browser/renderer_host/render_process_host_impl.h"
+#include "content/browser/storage_partition_impl.h"
 #include "content/public/browser/content_browser_client.h"
 #include "content/public/browser/notification_service.h"
 #include "content/public/browser/notification_types.h"
@@ -17,9 +18,11 @@
 #include "content/public/common/url_constants.h"
 #include "net/base/registry_controlled_domains/registry_controlled_domain.h"
 
+using content::BrowserContext;
 using content::RenderProcessHost;
 using content::RenderProcessHostImpl;
 using content::SiteInstance;
+using content::StoragePartitionImpl;
 using content::WebUIControllerFactory;
 
 static bool IsURLSameAsAnySiteInstance(const GURL& url) {
@@ -93,8 +96,7 @@ RenderProcessHost* SiteInstanceImpl::GetProcess() {
 
   // Create a new process if ours went away or was reused.
   if (!process_) {
-    content::BrowserContext* browser_context =
-        browsing_instance_->browser_context();
+    BrowserContext* browser_context = browsing_instance_->browser_context();
 
     // If we should use process-per-site mode (either in general or for the
     // given site), then look for an existing RenderProcessHost for the site.
@@ -118,8 +120,11 @@ RenderProcessHost* SiteInstanceImpl::GetProcess() {
         process_ = render_process_host_factory_->CreateRenderProcessHost(
             browser_context);
       } else {
+        StoragePartitionImpl* partition =
+            static_cast<StoragePartitionImpl*>(
+                BrowserContext::GetStoragePartition(browser_context, this));
         process_ =
-            new RenderProcessHostImpl(browser_context,
+            new RenderProcessHostImpl(browser_context, partition,
                                       site_.SchemeIs(chrome::kGuestScheme));
       }
     }
@@ -154,8 +159,7 @@ void SiteInstanceImpl::SetSite(const GURL& url) {
   // Remember that this SiteInstance has been used to load a URL, even if the
   // URL is invalid.
   has_site_ = true;
-  content::BrowserContext* browser_context =
-      browsing_instance_->browser_context();
+  BrowserContext* browser_context = browsing_instance_->browser_context();
   site_ = GetSiteForURL(browser_context, url);
 
   // Now that we have a site, register it with the BrowsingInstance.  This
@@ -214,18 +218,18 @@ bool SiteInstanceImpl::HasWrongProcessForURL(const GURL& url) const {
       process_, browsing_instance_->browser_context(), site_url);
 }
 
-content::BrowserContext* SiteInstanceImpl::GetBrowserContext() const {
+BrowserContext* SiteInstanceImpl::GetBrowserContext() const {
   return browsing_instance_->browser_context();
 }
 
 /*static*/
-SiteInstance* SiteInstance::Create(content::BrowserContext* browser_context) {
+SiteInstance* SiteInstance::Create(BrowserContext* browser_context) {
   return new SiteInstanceImpl(new BrowsingInstance(browser_context));
 }
 
 /*static*/
-SiteInstance* SiteInstance::CreateForURL(
-    content::BrowserContext* browser_context, const GURL& url) {
+SiteInstance* SiteInstance::CreateForURL(BrowserContext* browser_context,
+                                         const GURL& url) {
   // This BrowsingInstance may be deleted if it returns an existing
   // SiteInstance.
   scoped_refptr<BrowsingInstance> instance(
@@ -234,7 +238,7 @@ SiteInstance* SiteInstance::CreateForURL(
 }
 
 /*static*/
-GURL SiteInstanceImpl::GetSiteForURL(content::BrowserContext* browser_context,
+GURL SiteInstanceImpl::GetSiteForURL(BrowserContext* browser_context,
                                      const GURL& real_url) {
   // TODO(fsamuel, creis): For some reason appID is not recognized as a host.
   if (real_url.SchemeIs(chrome::kGuestScheme))
@@ -274,7 +278,7 @@ GURL SiteInstanceImpl::GetSiteForURL(content::BrowserContext* browser_context,
 }
 
 /*static*/
-bool SiteInstance::IsSameWebSite(content::BrowserContext* browser_context,
+bool SiteInstance::IsSameWebSite(BrowserContext* browser_context,
                                  const GURL& real_url1,
                                  const GURL& real_url2) {
   GURL url1 = SiteInstanceImpl::GetEffectiveURL(browser_context, real_url1);
@@ -303,9 +307,8 @@ bool SiteInstance::IsSameWebSite(content::BrowserContext* browser_context,
 }
 
 /*static*/
-GURL SiteInstanceImpl::GetEffectiveURL(
-    content::BrowserContext* browser_context,
-    const GURL& url) {
+GURL SiteInstanceImpl::GetEffectiveURL(BrowserContext* browser_context,
+                                       const GURL& url) {
   return content::GetContentClient()->browser()->
       GetEffectiveURL(browser_context, url);
 }
@@ -327,4 +330,3 @@ void SiteInstanceImpl::LockToOrigin() {
     policy->LockToOrigin(process_->GetID(), site_);
   }
 }
-
diff --git a/content/browser/site_instance_impl_unittest.cc b/content/browser/site_instance_impl_unittest.cc
index bd7997d..45d1600 100644
--- a/content/browser/site_instance_impl_unittest.cc
+++ b/content/browser/site_instance_impl_unittest.cc
@@ -135,14 +135,20 @@ class SiteInstanceTest : public testing::Test {
 
     content::GetContentClient()->set_browser_for_testing(old_browser_client_);
     content::SetContentClient(old_client_);
-    MessageLoop::current()->RunAllPending();
-    message_loop_.RunAllPending();
   }
 
   void set_privileged_process_id(int process_id) {
     browser_client_.set_privileged_process_id(process_id);
   }
 
+  void DrainMessageLoops() {
+    // We don't just do this in TearDown() because we create TestBrowserContext
+    // objects in each test, which will be destructed before
+    // TearDown() is called.
+    MessageLoop::current()->RunAllPending();
+    message_loop_.RunAllPending();
+  }
+
  private:
   MessageLoopForUI message_loop_;
   content::TestBrowserThread ui_thread_;
@@ -258,7 +264,7 @@ TEST_F(SiteInstanceTest, SiteInstanceDestructor) {
 
   // Make sure that we flush any messages related to the above WebContentsImpl
   // destruction.
-  MessageLoop::current()->RunAllPending();
+  DrainMessageLoops();
 
   EXPECT_EQ(2, site_delete_counter);
   EXPECT_EQ(2, browsing_delete_counter);
@@ -303,6 +309,8 @@ TEST_F(SiteInstanceTest, CloneNavigationEntry) {
 
   // Both BrowsingInstances are also now deleted
   EXPECT_EQ(2, browsing_delete_counter);
+
+  DrainMessageLoops();
 }
 
 // Test to ensure GetProcess returns and creates processes correctly.
@@ -322,6 +330,8 @@ TEST_F(SiteInstanceTest, GetProcess) {
   scoped_ptr<content::RenderProcessHost> host2(instance2->GetProcess());
   EXPECT_TRUE(host2.get() != NULL);
   EXPECT_NE(host1.get(), host2.get());
+
+  DrainMessageLoops();
 }
 
 // Test to ensure SetSite and site() work properly.
@@ -335,6 +345,8 @@ TEST_F(SiteInstanceTest, SetSite) {
   EXPECT_EQ(GURL("http://google.com"), instance->GetSite());
 
   EXPECT_TRUE(instance->HasSite());
+
+  DrainMessageLoops();
 }
 
 // Test to ensure GetSiteForURL properly returns sites for URLs.
@@ -368,6 +380,8 @@ TEST_F(SiteInstanceTest, GetSiteForURL) {
   // "file://home/" as the site, which seems broken.
   // test_url = GURL("file://home/");
   // EXPECT_EQ(GURL(), SiteInstanceImpl::GetSiteForURL(NULL, test_url));
+
+  DrainMessageLoops();
 }
 
 // Test of distinguishing URLs from different sites.  Most of this logic is
@@ -394,6 +408,8 @@ TEST_F(SiteInstanceTest, IsSameWebSite) {
   EXPECT_TRUE(SiteInstance::IsSameWebSite(NULL, url_javascript, url_foo));
   EXPECT_TRUE(SiteInstance::IsSameWebSite(NULL, url_javascript, url_foo_https));
   EXPECT_TRUE(SiteInstance::IsSameWebSite(NULL, url_javascript, url_foo_port));
+
+  DrainMessageLoops();
 }
 
 // Test to ensure that there is only one SiteInstance per site in a given
@@ -468,6 +484,8 @@ TEST_F(SiteInstanceTest, OneSiteInstancePerSite) {
 
   // browsing_instances will be deleted when their SiteInstances are deleted.
   // The processes will be unregistered when the RPH scoped_ptrs go away.
+
+  DrainMessageLoops();
 }
 
 // Test to ensure that there is only one RenderProcessHost per site for an
@@ -553,6 +571,8 @@ TEST_F(SiteInstanceTest, OneSiteInstancePerSiteInBrowserContext) {
 
   // browsing_instances will be deleted when their SiteInstances are deleted.
   // The processes will be unregistered when the RPH scoped_ptrs go away.
+
+  DrainMessageLoops();
 }
 
 static SiteInstanceImpl* CreateSiteInstance(
@@ -618,6 +638,8 @@ TEST_F(SiteInstanceTest, ProcessSharingByType) {
   }
 
   STLDeleteContainerPointers(hosts.begin(), hosts.end());
+
+  DrainMessageLoops();
 }
 
 // Test to ensure that HasWrongProcessForURL behaves properly for different
@@ -650,4 +672,6 @@ TEST_F(SiteInstanceTest, HasWrongProcessForURL) {
       GURL("javascript:alert(document.location.href);")));
 
   EXPECT_TRUE(instance->HasWrongProcessForURL(GURL("chrome://settings")));
+
+  DrainMessageLoops();
 }
diff --git a/content/browser/storage_partition.h b/content/browser/storage_partition.h
deleted file mode 100644
index ee6885e..0000000
--- a/content/browser/storage_partition.h
+++ /dev/null
@@ -1,77 +0,0 @@
-// 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_STORAGE_PARTITION_H_
-#define CONTENT_BROWSER_STORAGE_PARTITION_H_
-
-#include "base/file_path.h"
-#include "base/memory/ref_counted.h"
-
-namespace fileapi {
-class FileSystemContext;
-}
-
-namespace quota {
-class QuotaManager;
-}
-
-namespace webkit_database {
-class DatabaseTracker;
-}
-
-class ChromeAppCacheService;
-class DOMStorageContextImpl;
-
-namespace content {
-
-class BrowserContext;
-class IndexedDBContext;
-
-// Defines the what persistent state a child process can access.
-//
-// The StoragePartition defines the view each child process has of the
-// persistent state inside the BrowserContext. This is used to implement
-// isolated storage where a renderer with isolated storage cannot see
-// the cookies, localStorage, etc., that normal web renderers have access to.
-class StoragePartition {
- public:
-  ~StoragePartition();
-
-  // TODO(ajwong): Break the direct dependency on |context|. We only
-  // need 3 pieces of info from it.
-  static StoragePartition* Create(BrowserContext* context,
-                                  const FilePath& partition_path);
-
-  quota::QuotaManager* quota_manager() { return quota_manager_; }
-  ChromeAppCacheService* appcache_service() { return appcache_service_; }
-  fileapi::FileSystemContext* filesystem_context() {
-    return filesystem_context_;
-  }
-  webkit_database::DatabaseTracker* database_tracker() {
-    return database_tracker_;
-  }
-  DOMStorageContextImpl* dom_storage_context() { return dom_storage_context_; }
-  IndexedDBContext* indexed_db_context() { return indexed_db_context_; }
-
- private:
-  StoragePartition(const FilePath& partition_path,
-                   quota::QuotaManager* quota_manager,
-                   ChromeAppCacheService* appcache_service,
-                   fileapi::FileSystemContext* filesystem_context,
-                   webkit_database::DatabaseTracker* database_tracker,
-                   DOMStorageContextImpl* dom_storage_context,
-                   IndexedDBContext* indexed_db_context);
-
-  FilePath partition_path_;
-  scoped_refptr<quota::QuotaManager> quota_manager_;
-  scoped_refptr<ChromeAppCacheService> appcache_service_;
-  scoped_refptr<fileapi::FileSystemContext> filesystem_context_;
-  scoped_refptr<webkit_database::DatabaseTracker> database_tracker_;
-  scoped_refptr<DOMStorageContextImpl> dom_storage_context_;
-  scoped_refptr<IndexedDBContext> indexed_db_context_;
-};
-
-}  // namespace content
-
-#endif  // CONTENT_BROWSER_STORAGE_PARTITION_H_
diff --git a/content/browser/storage_partition.cc b/content/browser/storage_partition_impl.cc
index b6ed8c2..e906a6a 100644
--- a/content/browser/storage_partition.cc
+++ b/content/browser/storage_partition_impl.cc
@@ -2,12 +2,9 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-#include "content/browser/storage_partition.h"
+#include "content/browser/storage_partition_impl.h"
 
-#include "content/browser/appcache/chrome_appcache_service.h"
-#include "content/browser/dom_storage/dom_storage_context_impl.h"
 #include "content/browser/fileapi/browser_file_system_helper.h"
-#include "content/browser/in_process_webkit/indexed_db_context_impl.h"
 #include "content/public/browser/browser_context.h"
 #include "content/public/browser/browser_thread.h"
 #include "webkit/database/database_tracker.h"
@@ -15,14 +12,14 @@
 
 namespace content {
 
-StoragePartition::StoragePartition(
+StoragePartitionImpl::StoragePartitionImpl(
     const FilePath& partition_path,
     quota::QuotaManager* quota_manager,
     ChromeAppCacheService* appcache_service,
     fileapi::FileSystemContext* filesystem_context,
     webkit_database::DatabaseTracker* database_tracker,
     DOMStorageContextImpl* dom_storage_context,
-    IndexedDBContext* indexed_db_context)
+    IndexedDBContextImpl* indexed_db_context)
     : partition_path_(partition_path),
       quota_manager_(quota_manager),
       appcache_service_(appcache_service),
@@ -32,24 +29,25 @@ StoragePartition::StoragePartition(
       indexed_db_context_(indexed_db_context) {
 }
 
-StoragePartition::~StoragePartition() {
+StoragePartitionImpl::~StoragePartitionImpl() {
   // These message loop checks are just to avoid leaks in unittests.
-  if (database_tracker() &&
+  if (GetDatabaseTracker() &&
       BrowserThread::IsMessageLoopValid(BrowserThread::FILE)) {
     BrowserThread::PostTask(
         BrowserThread::FILE, FROM_HERE,
         base::Bind(&webkit_database::DatabaseTracker::Shutdown,
-                   database_tracker()));
+                   GetDatabaseTracker()));
   }
 
-  if (dom_storage_context())
-    dom_storage_context()->Shutdown();
+  if (GetDOMStorageContext())
+    GetDOMStorageContext()->Shutdown();
 }
 
 // TODO(ajwong): Break the direct dependency on |context|. We only
 // need 3 pieces of info from it.
-StoragePartition* StoragePartition::Create(BrowserContext* context,
-                                           const FilePath& partition_path) {
+StoragePartitionImpl* StoragePartitionImpl::Create(
+    BrowserContext* context,
+    const FilePath& partition_path) {
   // Ensure that these methods are called on the UI thread, except for
   // unittests where a UI thread might not have been created.
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI) ||
@@ -92,13 +90,37 @@ StoragePartition* StoragePartition::Create(BrowserContext* context,
   scoped_refptr<ChromeAppCacheService> appcache_service =
       new ChromeAppCacheService(quota_manager->proxy());
 
-  return new StoragePartition(partition_path,
-                              quota_manager,
-                              appcache_service,
-                              filesystem_context,
-                              database_tracker,
-                              dom_storage_context,
-                              indexed_db_context);
+  return new StoragePartitionImpl(partition_path,
+                                  quota_manager,
+                                  appcache_service,
+                                  filesystem_context,
+                                  database_tracker,
+                                  dom_storage_context,
+                                  indexed_db_context);
+}
+
+quota::QuotaManager* StoragePartitionImpl::GetQuotaManager() {
+  return quota_manager_;
+}
+
+ChromeAppCacheService* StoragePartitionImpl::GetAppCacheService() {
+  return appcache_service_;
+}
+
+fileapi::FileSystemContext* StoragePartitionImpl::GetFileSystemContext() {
+  return filesystem_context_;
+}
+
+webkit_database::DatabaseTracker* StoragePartitionImpl::GetDatabaseTracker() {
+  return database_tracker_;
+}
+
+DOMStorageContextImpl* StoragePartitionImpl::GetDOMStorageContext() {
+  return dom_storage_context_;
+}
+
+IndexedDBContextImpl* StoragePartitionImpl::GetIndexedDBContext() {
+  return indexed_db_context_;
 }
 
 }  // namespace content
diff --git a/content/browser/storage_partition_impl.h b/content/browser/storage_partition_impl.h
new file mode 100644
index 0000000..9ab7fc3
--- /dev/null
+++ b/content/browser/storage_partition_impl.h
@@ -0,0 +1,57 @@
+// 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_STORAGE_PARTITION_IMPL_H_
+#define CONTENT_BROWSER_STORAGE_PARTITION_IMPL_H_
+
+#include "base/compiler_specific.h"
+#include "base/file_path.h"
+#include "base/memory/ref_counted.h"
+#include "content/browser/appcache/chrome_appcache_service.h"
+#include "content/browser/dom_storage/dom_storage_context_impl.h"
+#include "content/browser/in_process_webkit/indexed_db_context_impl.h"
+#include "content/public/browser/storage_partition.h"
+
+namespace content {
+
+class StoragePartitionImpl : public StoragePartition {
+ public:
+  virtual ~StoragePartitionImpl();
+
+  // TODO(ajwong): Break the direct dependency on |context|. We only
+  // need 3 pieces of info from it.
+  static StoragePartitionImpl* Create(BrowserContext* context,
+                                      const FilePath& partition_path);
+
+  // StoragePartition interface.
+  virtual quota::QuotaManager* GetQuotaManager() OVERRIDE;
+  virtual ChromeAppCacheService* GetAppCacheService() OVERRIDE;
+  virtual fileapi::FileSystemContext* GetFileSystemContext() OVERRIDE;
+  virtual webkit_database::DatabaseTracker* GetDatabaseTracker() OVERRIDE;
+  virtual DOMStorageContextImpl* GetDOMStorageContext() OVERRIDE;
+  virtual IndexedDBContextImpl* GetIndexedDBContext() OVERRIDE;
+
+ private:
+  StoragePartitionImpl(const FilePath& partition_path,
+                       quota::QuotaManager* quota_manager,
+                       ChromeAppCacheService* appcache_service,
+                       fileapi::FileSystemContext* filesystem_context,
+                       webkit_database::DatabaseTracker* database_tracker,
+                       DOMStorageContextImpl* dom_storage_context,
+                       IndexedDBContextImpl* indexed_db_context);
+
+  FilePath partition_path_;
+  scoped_refptr<quota::QuotaManager> quota_manager_;
+  scoped_refptr<ChromeAppCacheService> appcache_service_;
+  scoped_refptr<fileapi::FileSystemContext> filesystem_context_;
+  scoped_refptr<webkit_database::DatabaseTracker> database_tracker_;
+  scoped_refptr<DOMStorageContextImpl> dom_storage_context_;
+  scoped_refptr<IndexedDBContextImpl> indexed_db_context_;
+
+  DISALLOW_COPY_AND_ASSIGN(StoragePartitionImpl);
+};
+
+}  // namespace content
+
+#endif  // CONTENT_BROWSER_STORAGE_PARTITION_IMPL_H_
diff --git a/content/browser/storage_partition_map.cc b/content/browser/storage_partition_impl_map.cc
index 2611370..fd62c98 100644
--- a/content/browser/storage_partition_map.cc
+++ b/content/browser/storage_partition_impl_map.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/storage_partition_map.h"
+#include "content/browser/storage_partition_impl_map.h"
 
 #include "base/bind.h"
 #include "base/callback.h"
@@ -11,7 +11,7 @@
 #include "base/string_util.h"
 #include "content/browser/appcache/chrome_appcache_service.h"
 #include "content/browser/resource_context_impl.h"
-#include "content/browser/storage_partition.h"
+#include "content/browser/storage_partition_impl.h"
 #include "content/public/browser/browser_context.h"
 #include "content/public/browser/browser_thread.h"
 #include "content/public/common/content_constants.h"
@@ -22,19 +22,20 @@ namespace content {
 const FilePath::CharType kStoragePartitionDirName[] =
     FILE_PATH_LITERAL("Storage Partitions");
 
-StoragePartitionMap::StoragePartitionMap(
+StoragePartitionImplMap::StoragePartitionImplMap(
     BrowserContext* browser_context)
     : browser_context_(browser_context) {
 }
 
-StoragePartitionMap::~StoragePartitionMap() {
+StoragePartitionImplMap::~StoragePartitionImplMap() {
   STLDeleteContainerPairSecondPointers(partitions_.begin(),
                                        partitions_.end());
 }
 
-StoragePartition* StoragePartitionMap::Get(const std::string& partition_id) {
+StoragePartitionImpl* StoragePartitionImplMap::Get(
+    const std::string& partition_id) {
   // Find the previously created partition if it's available.
-  std::map<std::string, StoragePartition*>::const_iterator it =
+  std::map<std::string, StoragePartitionImpl*>::const_iterator it =
       partitions_.find(partition_id);
   if (it != partitions_.end())
     return it->second;
@@ -42,14 +43,14 @@ StoragePartition* StoragePartitionMap::Get(const std::string& partition_id) {
   // There was no previous partition, so let's make a new one.
   FilePath partition_path = browser_context_->GetPath();
   if (!partition_id.empty()) {
-    // TODO(ajwong): This should check the pth is valid?
+    // TODO(ajwong): This should check the path is valid?
     CHECK(IsStringASCII(partition_id));
     partition_path = partition_path.Append(kStoragePartitionDirName)
         .AppendASCII(partition_id);
   }
 
-  StoragePartition* storage_partition =
-      StoragePartition::Create(browser_context_, partition_path);
+  StoragePartitionImpl* storage_partition =
+      StoragePartitionImpl::Create(browser_context_, partition_path);
   partitions_[partition_id] = storage_partition;
 
   PostCreateInitialization(storage_partition, partition_path);
@@ -64,25 +65,25 @@ StoragePartition* StoragePartitionMap::Get(const std::string& partition_id) {
   return storage_partition;
 }
 
-void StoragePartitionMap::ForEach(
-    const base::Callback<void(StoragePartition*)>& callback) {
-  for (std::map<std::string, StoragePartition*>::const_iterator it =
+void StoragePartitionImplMap::ForEach(
+    const BrowserContext::StoragePartitionCallback& callback) {
+  for (std::map<std::string, StoragePartitionImpl*>::const_iterator it =
            partitions_.begin();
        it != partitions_.end();
        ++it) {
-    callback.Run(it->second);
+    callback.Run(it->first, it->second);
   }
 }
 
-void StoragePartitionMap::PostCreateInitialization(
-    StoragePartition* partition,
+void StoragePartitionImplMap::PostCreateInitialization(
+    StoragePartitionImpl* partition,
     const FilePath& partition_path) {
   // Check first to avoid memory leak in unittests.
   if (BrowserThread::IsMessageLoopValid(BrowserThread::IO)) {
     BrowserThread::PostTask(
         BrowserThread::IO, FROM_HERE,
         base::Bind(&ChromeAppCacheService::InitializeOnIOThread,
-                   partition->appcache_service(),
+                   partition->GetAppCacheService(),
                    browser_context_->IsOffTheRecord() ? FilePath() :
                        partition_path.Append(kAppCacheDirname),
                        browser_context_->GetResourceContext(),
diff --git a/content/browser/storage_partition_map.h b/content/browser/storage_partition_impl_map.h
index bcebac1..d4a66e7 100644
--- a/content/browser/storage_partition_map.h
+++ b/content/browser/storage_partition_impl_map.h
@@ -10,25 +10,26 @@
 
 #include "base/callback_forward.h"
 #include "base/supports_user_data.h"
+#include "content/public/browser/browser_context.h"
 
 class FilePath;
 
 namespace content {
 
 class BrowserContext;
-class StoragePartition;
+class StoragePartitionImpl;
 
 // A std::string to StoragePartition map for use with SupportsUserData APIs.
-class StoragePartitionMap : public base::SupportsUserData::Data {
+class StoragePartitionImplMap : public base::SupportsUserData::Data {
  public:
-  explicit StoragePartitionMap(BrowserContext* browser_context);
+  explicit StoragePartitionImplMap(BrowserContext* browser_context);
 
-  virtual ~StoragePartitionMap();
+  virtual ~StoragePartitionImplMap();
 
   // This map retains ownership of the returned StoragePartition objects.
-  StoragePartition* Get(const std::string& partition_id);
+  StoragePartitionImpl* Get(const std::string& partition_id);
 
-  void ForEach(const base::Callback<void(StoragePartition*)>& callback);
+  void ForEach(const BrowserContext::StoragePartitionCallback& callback);
 
  private:
   // This must always be called *after* |partition| has been added to the
@@ -37,11 +38,11 @@ class StoragePartitionMap : public base::SupportsUserData::Data {
   // TODO(ajwong): Is there a way to make it so that Get()'s implementation
   // doesn't need to be aware of this ordering?  Revisit when refactoring
   // ResourceContext and AppCache to respect storage partitions.
-  void PostCreateInitialization(StoragePartition* partition,
+  void PostCreateInitialization(StoragePartitionImpl* partition,
                                 const FilePath& partition_path);
 
   BrowserContext* browser_context_;  // Not Owned.
-  std::map<std::string, StoragePartition*> partitions_;
+  std::map<std::string, StoragePartitionImpl*> partitions_;
 };
 
 }  // namespace content
diff --git a/content/browser/web_contents/interstitial_page_impl.cc b/content/browser/web_contents/interstitial_page_impl.cc
index 1d53cb1..f2ac72e 100644
--- a/content/browser/web_contents/interstitial_page_impl.cc
+++ b/content/browser/web_contents/interstitial_page_impl.cc
@@ -32,6 +32,7 @@
 #include "content/public/browser/invalidate_type.h"
 #include "content/public/browser/notification_service.h"
 #include "content/public/browser/notification_source.h"
+#include "content/public/browser/storage_partition.h"
 #include "content/public/browser/web_contents_view.h"
 #include "content/public/common/bindings_policy.h"
 #include "content/public/common/page_transition_types.h"
@@ -487,14 +488,10 @@ RenderViewHost* InterstitialPageImpl::CreateRenderViewHost() {
   BrowserContext* browser_context = web_contents()->GetBrowserContext();
   scoped_refptr<SiteInstance> site_instance =
       SiteInstance::Create(browser_context);
-  const std::string& partition_id =
-      content::GetContentClient()->browser()->
-          GetStoragePartitionIdForSiteInstance(browser_context,
-                                               site_instance);
   DOMStorageContextImpl* dom_storage_context =
       static_cast<DOMStorageContextImpl*>(
-          BrowserContext::GetDOMStorageContextByPartitionId(browser_context,
-                                                            partition_id));
+          BrowserContext::GetStoragePartition(
+              browser_context, site_instance)->GetDOMStorageContext());
   SessionStorageNamespaceImpl* session_storage_namespace_impl =
       new SessionStorageNamespaceImpl(dom_storage_context);
 
diff --git a/content/browser/web_contents/navigation_controller_impl.cc b/content/browser/web_contents/navigation_controller_impl.cc
index 28ad4a4..877a446 100644
--- a/content/browser/web_contents/navigation_controller_impl.cc
+++ b/content/browser/web_contents/navigation_controller_impl.cc
@@ -27,6 +27,7 @@
 #include "content/public/browser/navigation_details.h"
 #include "content/public/browser/notification_service.h"
 #include "content/public/browser/notification_types.h"
+#include "content/public/browser/storage_partition.h"
 #include "content/public/browser/user_metrics.h"
 #include "content/public/browser/web_contents_delegate.h"
 #include "content/public/common/content_client.h"
@@ -1269,11 +1270,15 @@ NavigationControllerImpl::GetSessionStorageNamespace(
     return it->second.get();
 
   // Create one if no one has accessed session storage for this partition yet.
+  //
+  // TODO(ajwong): Should this use the |partition_id| directly rather than
+  // re-lookup via |instance|?  http://crbug.com/142685
+  content::StoragePartition* partition =
+              BrowserContext::GetStoragePartition(browser_context_, instance);
   SessionStorageNamespaceImpl* session_storage_namespace =
       new SessionStorageNamespaceImpl(
           static_cast<DOMStorageContextImpl*>(
-              BrowserContext::GetDOMStorageContextByPartitionId(
-                  browser_context_, partition_id)));
+              partition->GetDOMStorageContext()));
   session_storage_namespace_map_[partition_id] = session_storage_namespace;
 
   return session_storage_namespace;
diff --git a/content/browser/web_contents/web_contents_impl.cc b/content/browser/web_contents/web_contents_impl.cc
index d4c3dafb..61d98d8 100644
--- a/content/browser/web_contents/web_contents_impl.cc
+++ b/content/browser/web_contents/web_contents_impl.cc
@@ -54,6 +54,7 @@
 #include "content/public/browser/notification_details.h"
 #include "content/public/browser/notification_service.h"
 #include "content/public/browser/resource_request_details.h"
+#include "content/public/browser/storage_partition.h"
 #include "content/public/browser/user_metrics.h"
 #include "content/public/browser/web_contents_delegate.h"
 #include "content/public/browser/web_contents_observer.h"
@@ -1247,14 +1248,17 @@ void WebContentsImpl::CreateNewWindow(
                           params.opener_suppressed ? NULL : this);
 
   // We must assign the SessionStorageNamespace before calling Init().
+  //
+  // http://crbug.com/142685
   const std::string& partition_id =
       content::GetContentClient()->browser()->
           GetStoragePartitionIdForSiteInstance(GetBrowserContext(),
                                                site_instance);
+  content::StoragePartition* partition =
+      BrowserContext::GetStoragePartition(GetBrowserContext(),
+                                          site_instance);
   DOMStorageContextImpl* dom_storage_context =
-      static_cast<DOMStorageContextImpl*>(
-          BrowserContext::GetDOMStorageContextByPartitionId(
-              GetBrowserContext(), partition_id));
+      static_cast<DOMStorageContextImpl*>(partition->GetDOMStorageContext());
   SessionStorageNamespaceImpl* session_storage_namespace_impl =
       static_cast<SessionStorageNamespaceImpl*>(session_storage_namespace);
   CHECK(session_storage_namespace_impl->IsFromContext(dom_storage_context));
diff --git a/content/content_browser.gypi b/content/content_browser.gypi
index 23178e3..3fcf64d 100644
--- a/content/content_browser.gypi
+++ b/content/content_browser.gypi
@@ -152,6 +152,7 @@
     'public/browser/speech_recognition_session_config.h',
     'public/browser/speech_recognition_session_context.cc',
     'public/browser/speech_recognition_session_context.h',
+    'public/browser/storage_partition.h',
     'public/browser/trace_controller.h',
     'public/browser/trace_subscriber.h',
     'public/browser/user_metrics.h',
@@ -749,12 +750,12 @@
     'browser/ssl/ssl_policy_backend.h',
     'browser/ssl/ssl_policy.cc',
     'browser/ssl/ssl_policy.h',
-    'browser/storage_partition.cc',
-    'browser/storage_partition.h',
-    'browser/storage_partition_map.cc',
-    'browser/storage_partition_map.h',
     'browser/ssl/ssl_request_info.cc',
     'browser/ssl/ssl_request_info.h',
+    'browser/storage_partition_impl.cc',
+    'browser/storage_partition_impl.h',
+    'browser/storage_partition_impl_map.cc',
+    'browser/storage_partition_impl_map.h',
     'browser/system_message_window_win.cc',
     'browser/system_message_window_win.h',
     'browser/tcmalloc_internals_request_job.cc',
diff --git a/content/public/browser/browser_context.h b/content/public/browser/browser_context.h
index cfe4d53..2acf400 100644
--- a/content/public/browser/browser_context.h
+++ b/content/public/browser/browser_context.h
@@ -5,6 +5,7 @@
 #ifndef CONTENT_PUBLIC_BROWSER_BROWSER_CONTEXT_H_
 #define CONTENT_PUBLIC_BROWSER_BROWSER_CONTEXT_H_
 
+#include "base/callback_forward.h"
 #include "base/hash_tables.h"
 #include "base/supports_user_data.h"
 #include "content/common/content_export.h"
@@ -40,21 +41,22 @@ class DownloadManagerDelegate;
 class GeolocationPermissionContext;
 class IndexedDBContext;
 class ResourceContext;
+class SiteInstance;
 class SpeechRecognitionPreferences;
+class StoragePartition;
 
 // This class holds the context needed for a browsing session.
 // It lives on the UI thread. All these methods must only be called on the UI
 // thread.
 class CONTENT_EXPORT BrowserContext : public base::SupportsUserData {
  public:
+  // Used in ForEachStoragePartition(). The first argument is the partition id.
+  // The second argument is the StoragePartition object for that partition id.
+  typedef base::Callback<void(const std::string&, StoragePartition*)>
+      StoragePartitionCallback;
+
   static DownloadManager* GetDownloadManager(BrowserContext* browser_context);
   static quota::QuotaManager* GetQuotaManager(BrowserContext* browser_context);
-  static DOMStorageContext* GetDefaultDOMStorageContext(
-      BrowserContext* browser_context);
-  static DOMStorageContext* GetDOMStorageContext(
-      BrowserContext* browser_context, int renderer_child_id);
-  static content::DOMStorageContext* GetDOMStorageContextByPartitionId(
-      BrowserContext* browser_context, const std::string& partition_id);
   static IndexedDBContext* GetIndexedDBContext(BrowserContext* browser_context);
   static webkit_database::DatabaseTracker* GetDatabaseTracker(
       BrowserContext* browser_context);
@@ -63,6 +65,17 @@ class CONTENT_EXPORT BrowserContext : public base::SupportsUserData {
   static fileapi::FileSystemContext* GetFileSystemContext(
       BrowserContext* browser_context);
 
+  static content::StoragePartition* GetStoragePartition(
+      BrowserContext* browser_context, SiteInstance* site_instance);
+  static void ForEachStoragePartition(
+      BrowserContext* browser_context,
+      const StoragePartitionCallback& callback);
+
+  // DON'T USE THIS. GetDefaultStoragePartition() is going away.
+  // Use GetStoragePartition() instead. Ask ajwong@ if you have problems.
+  static content::StoragePartition* GetDefaultStoragePartition(
+      BrowserContext* browser_context);
+
   // Ensures that the corresponding ResourceContext is initialized. Normally the
   // BrowserContext initializs the corresponding getters when its objects are
   // created, but if the embedder wants to pass the ResourceContext to another
diff --git a/content/public/browser/resource_context.h b/content/public/browser/resource_context.h
index 0bdcff8..8304159 100644
--- a/content/public/browser/resource_context.h
+++ b/content/public/browser/resource_context.h
@@ -5,6 +5,7 @@
 #ifndef CONTENT_PUBLIC_BROWSER_RESOURCE_CONTEXT_H_
 #define CONTENT_PUBLIC_BROWSER_RESOURCE_CONTEXT_H_
 
+#include "base/basictypes.h"
 #include "base/supports_user_data.h"
 #include "content/common/content_export.h"
 
diff --git a/content/public/browser/storage_partition.h b/content/public/browser/storage_partition.h
new file mode 100644
index 0000000..d7c1363
--- /dev/null
+++ b/content/public/browser/storage_partition.h
@@ -0,0 +1,53 @@
+// 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_PUBLIC_BROWSER_STORAGE_PARTITION_H_
+#define CONTENT_PUBLIC_BROWSER_STORAGE_PARTITION_H_
+
+#include "base/basictypes.h"
+
+namespace appcache {
+class AppCacheService;
+}
+
+namespace fileapi {
+class FileSystemContext;
+}
+
+namespace quota {
+class QuotaManager;
+}
+
+namespace webkit_database {
+class DatabaseTracker;
+}
+
+namespace content {
+
+class BrowserContext;
+class IndexedDBContext;
+class DOMStorageContext;
+
+// Defines what persistent state a child process can access.
+//
+// The StoragePartition defines the view each child process has of the
+// persistent state inside the BrowserContext. This is used to implement
+// isolated storage where a renderer with isolated storage cannot see
+// the cookies, localStorage, etc., that normal web renderers have access to.
+class StoragePartition {
+ public:
+  virtual quota::QuotaManager* GetQuotaManager() = 0;
+  virtual appcache::AppCacheService* GetAppCacheService() = 0;
+  virtual fileapi::FileSystemContext* GetFileSystemContext() = 0;
+  virtual webkit_database::DatabaseTracker* GetDatabaseTracker() = 0;
+  virtual DOMStorageContext* GetDOMStorageContext() = 0;
+  virtual IndexedDBContext* GetIndexedDBContext() = 0;
+
+ protected:
+  virtual ~StoragePartition() {}
+};
+
+}  // namespace content
+
+#endif  // CONTENT_PUBLIC_BROWSER_STORAGE_PARTITION_H_