WIP: Introduce per-TabContents PrefService.

chrome/browser/profiles/profile.h

Index: chrome/browser/profiles/profile.h
diff --git a/chrome/browser/profiles/profile.h b/chrome/browser/profiles/profile.h
index c2ba480cdc5f74c232749f987fdaa115965cf0d3..12c919b2e69638181c5f86e938418dbd7c6aa666 100644
--- a/chrome/browser/profiles/profile.h
+++ b/chrome/browser/profiles/profile.h
@@ -35,13 +35,13 @@ class SandboxedFileSystemContext;
 }
 
 namespace history {
-class TopSites;
 class ShortcutsBackend;
+class TopSites;
 }
 
 namespace net {
-class TransportSecurityState;
 class SSLConfigService;
+class TransportSecurityState;
 }
 
 namespace prerender {
@@ -82,6 +82,7 @@ class ProtocolHandlerRegistry;
 class SQLitePersistentCookieStore;
 class SSLConfigServiceManager;
 class SpellCheckHost;
+class TabContents;
 class TemplateURLFetcher;
 class TokenService;
 class TransportSecurityPersister;
@@ -344,6 +345,16 @@ class Profile : public content::BrowserContext {
   // time that this method is called.
   virtual PrefService* GetOffTheRecordPrefs() = 0;
 
+  // Retrieves a pointer to a special PrefService with overrides per
+  // TabContents. Non-user pref sources such as policy, command-line and
+  // extensions are shared with the profile's main pref service.
+  //
+  // Ideally, this would live in a per-TabContest context object, but since on

[Avi (use Gerrit), 2011/09/07 18:00:56]

What is a "per-TabContent (typo) context object"? You mean a TabContentsWrapper?

Perhaps a tab helper there? I'm not sure I understand the problem.

[Mattias Nissler (ping if slow), 2011/09/07 18:24:46]

Ah, I wasn't aware of TabContentsWrapper :) I'll move this to TabContentsWrapper
then.

Out of curiosity: Why isn't the TabContentsWrapper implementing BrowserContext
then, but Profile? Seems like inverted dependencies to uninitiated me.

+  // the Chrome side there is no per-TabContents context object, it's here in
+  // Profile, which is the content::BrowserContext shared by potentially several
+  // TabContents.
+  virtual PrefService* GetPrefsForTabContents(TabContents* contents) = 0;

[Mattias Nissler (ping if slow), 2011/09/07 17:54:24]

This is the accessor for getting the per-TabContents PrefService. There's no
need to put it here, since the TabContents pointer gives us all we need. In
fact, it may be better to implement this as a static function somewhere?

+
   // Returns the TemplateURLFetcher for this profile. This is owned by the
   // profile.
   virtual TemplateURLFetcher* GetTemplateURLFetcher() = 0;