Implement {Start,Stop}CapturingKeyStrokes for Instant.

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 5a40934db34db89d88136bf9dbc53ec9fc1ee608..244af8ba813fb579b01cb0bd474a0f9f746cadab 100644
--- a/chrome/browser/ui/search/search_tab_helper.h
+++ b/chrome/browser/ui/search/search_tab_helper.h
@@ -43,6 +43,12 @@ class SearchTabHelper : public content::WebContentsObserver,
   // the notification system and shouldn't call this method.
   void NavigationEntryUpdated();
 
+  // Invoked when the searchbox on the Instant overlay receives focus.
+  void OnWebSearchBoxFocus();
+
+  // Invoked when the searchbox on the Instant overlay loses focus.
+  void OnWebSearchBoxBlur();
+
   // Overridden from contents::WebContentsObserver:
   virtual void NavigateToPendingEntry(
       const GURL& url,