Moved theme related state from BrowserInstantController to InstantService.

chrome/browser/ui/search/search_tab_helper.h

Index: chrome/browser/ui/search/search_tab_helper.h
diff --git a/chrome/browser/ui/search/search_tab_helper.h b/chrome/browser/ui/search/search_tab_helper.h
index 8dd771100bd814bded3345f691479189a6b21cb2..bdb5d63b39d713a58e5fb7e21864e20535910002 100644
--- a/chrome/browser/ui/search/search_tab_helper.h
+++ b/chrome/browser/ui/search/search_tab_helper.h
@@ -9,6 +9,7 @@
 
 #include "base/basictypes.h"
 #include "base/compiler_specific.h"
+#include "base/memory/scoped_ptr.h"
 #include "chrome/browser/ui/search/search_model.h"
 #include "chrome/common/instant_types.h"
 #include "content/public/browser/notification_observer.h"
@@ -50,6 +51,11 @@ class SearchTabHelper : public content::NotificationObserver,
   bool UpdateLastKnownMostVisitedItems(
       const std::vector<InstantMostVisitedItem>& items);
 
+  // Updates |last_known_theme_info_| with |theme_info|.
+  // Returns false if |theme_info| matches the |last_known_theme_info_|.
+  bool UpdateLastKnownThemeBackgroundInfo(
+      const ThemeBackgroundInfo& theme_info);
+
  private:
   friend class content::WebContentsUserData<SearchTabHelper>;
 
@@ -89,6 +95,9 @@ class SearchTabHelper : public content::NotificationObserver,
   // Used to prevent sending duplicate IPC messages to the renderer.
   std::vector<InstantMostVisitedItem> last_known_most_visited_items_;
 
+  // Tracks the last known theme background details.
+  scoped_ptr<ThemeBackgroundInfo> last_known_theme_info_;

[samarth, 2013/06/19 18:30:02]

As discussed offline, let's track this in the renderer. So we'll always send an
IPC from InstantController in ThemeInfoChanged(). The renderer (searchbox.cc)
should then make sure we don't send duplicate events.

If this works, we can make the same change for most visited.

[kmadhusu, 2013/06/19 21:31:01]

Done.

+
   DISALLOW_COPY_AND_ASSIGN(SearchTabHelper);
 };