Introduce per-tab preferences service.

chrome/browser/ui/tab_contents/tab_contents_wrapper.h

Index: chrome/browser/ui/tab_contents/tab_contents_wrapper.h
diff --git a/chrome/browser/ui/tab_contents/tab_contents_wrapper.h b/chrome/browser/ui/tab_contents/tab_contents_wrapper.h
index f99daf5acf6d985f62db9215485cb1e7878d9ad4..84b71433eb06306cf05cafc6c9460eea45cad9ba 100644
--- a/chrome/browser/ui/tab_contents/tab_contents_wrapper.h
+++ b/chrome/browser/ui/tab_contents/tab_contents_wrapper.h
@@ -40,6 +40,7 @@ class OmniboxSearchHint;
 class PasswordManager;
 class PasswordManagerDelegate;
 class PluginObserver;
+class PrefService;
 class Profile;
 class RestoreTabHelper;
 class SadTabObserver;
@@ -292,6 +293,9 @@ class TabContentsWrapper : public TabContentsObserver,
   scoped_ptr<PasswordManagerDelegate> password_manager_delegate_;
   scoped_ptr<PasswordManager> password_manager_;
 
+  // Allows overriding user preferences per tab.
+  scoped_ptr<PrefService> per_tab_prefs_;

[Avi (use Gerrit), 2011/11/17 18:23:33]

Since there is no getter, this isn't a tab helper and doesn't belong in this
section (see the comment on line 275). Move this to the observer section, line
328 or wherever it fits alphabetically, and move the allocation in the .cc file
too.

[mnaganov (inactive), 2011/11/17 18:27:00]

I'm not yet sure how to use this. I need to override WebKit prefs using
per_tab_prefs_ when getting WebPreferences from TabContents. It will become more
clear when I'll add plumbing to other places.

[mnaganov (inactive), 2011/11/17 19:54:43]

I have moved this into the "observers" section as you suggested.

+
   scoped_ptr<prerender::PrerenderTabHelper> prerender_tab_helper_;
 
   // Handles print job for this contents.