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..124169e5f0b9fc5605718d40d06da9f607c31d3b 100644
--- a/chrome/browser/ui/search/search_tab_helper.h
+++ b/chrome/browser/ui/search/search_tab_helper.h
@@ -50,6 +50,11 @@ 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 +94,9 @@ 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.
+  ThemeBackgroundInfo last_known_theme_info_;
+
   DISALLOW_COPY_AND_ASSIGN(SearchTabHelper);
 };