Move SessionStorageNamespace entirely into NavigationController and support StoragePartitions.

chrome/browser/chrome_content_browser_client.cc

Index: chrome/browser/chrome_content_browser_client.cc
diff --git a/chrome/browser/chrome_content_browser_client.cc b/chrome/browser/chrome_content_browser_client.cc
index d45f4df51a35ffe34f69b4c7e5f045158492940d..f34a66946bc3aa300ad4efe07b4496313a6246fd 100644
--- a/chrome/browser/chrome_content_browser_client.cc
+++ b/chrome/browser/chrome_content_browser_client.cc
@@ -413,14 +413,64 @@ std::string ChromeContentBrowserClient::GetStoragePartitionIdForChildProcess(
   Profile* profile = Profile::FromBrowserContext(browser_context);
   ExtensionService* extension_service =
       extensions::ExtensionSystem::Get(profile)->extension_service();
+  std::string partition_id;
   if (extension_service) {
     const extensions::Extension* installed_app = extension_service->
         GetInstalledAppForRenderer(child_process_id);

[Charlie Reis, 2012/08/06 20:38:30]

Huh, this API doesn't make sense.  There can be multiple apps in the same
process.  I've filed http://crbug.com/140856.

As you mentioned offline, it does work for this case, because isolated apps
won't share a process.  Please add a comment to that effect.

     if (installed_app && installed_app->is_storage_isolated()) {
-      return installed_app->id();
+      partition_id = installed_app->id();
     }
   }
-  return std::string();
+
+  // Enforce that IsValidStoragePartitionId() implementation stays in sync.
+  DCHECK(IsValidStoragePartitionId(browser_context, partition_id));
+  return partition_id;
+}
+
+std::string ChromeContentBrowserClient::GetStoragePartitionIdForSiteInstance(
+    content::BrowserContext* browser_context,
+    SiteInstance* instance) {
+  // In chrome, we use the extension ID as the partition ID. This works well
+  // because the extension ID fits the partition ID pattern and currently only
+  // apps can designate that storage should be isolated.
+  Profile* profile = Profile::FromBrowserContext(browser_context);
+  ExtensionService* extension_service =
+      extensions::ExtensionSystem::Get(profile)->extension_service();
+  std::string partition_id;
+  if (extension_service) {
+    const Extension* extension = extension_service->extensions()->
+        GetExtensionOrAppByURL(ExtensionURLInfo(instance->GetSite()));

[Charlie Reis, 2012/08/06 20:38:30]

These two functions are identical except in how they acquire their Extension. 
Can you use a helper function instead?

[awong, 2012/08/08 18:08:28]

I'm not sure how I'd extract something that wouldn't look almost the same.

[Charlie Reis, 2012/08/13 19:39:21]

Even if we're just sharing the last few lines and the intro comment (using a
helper function that takes in an Extension and returns a partition ID), I think
that's worthwhile.  This is a policy that might change over time, and we should
avoid letting it get stale.

[awong, 2012/08/13 21:29:19]

Done.

+    if (extension && extension->is_storage_isolated()) {
+      partition_id = extension->id();
+    }
+  }
+
+  // Enforce that IsValidStoragePartitionId() implementation stays in sync.
+  DCHECK(IsValidStoragePartitionId(browser_context, partition_id));
+  return partition_id;
+}
+
+bool ChromeContentBrowserClient::IsValidStoragePartitionId(
+    content::BrowserContext* browser_context,
+    const std::string& partition_id) {
+  // The default ID is empty which is always allowed.
+  if (partition_id.empty()) {

[Charlie Reis, 2012/08/06 20:38:30]

nit: No braces.

[awong, 2012/08/08 18:08:28]

Done.

+    return true;
+  }
+
+  // If it isn't empty, then it must belong to an extension of some sort. Parse
+  // out the extension ID and make sure it is still installed.
+  Profile* profile = Profile::FromBrowserContext(browser_context);
+  ExtensionService* extension_service =
+      extensions::ExtensionSystem::Get(profile)->extension_service();
+  if (!extension_service) {
+    // No extension service means no storage partitions in Chrome.
+    return false;
+  }
+
+  // See if we can find an extension. The |partition_id| is the extension ID so
+  // no parsing needed to be done.
+  return extension_service->GetExtensionById(partition_id, false) != NULL;
 }
 
 content::WebContentsViewDelegate*