Implement {Start,Stop}CapturingKeyStrokes for Instant.

chrome/browser/ui/browser_instant_controller.h

Index: chrome/browser/ui/browser_instant_controller.h
diff --git a/chrome/browser/ui/browser_instant_controller.h b/chrome/browser/ui/browser_instant_controller.h
index ef23d3a3e6675241c1b40cdd55879e6654891223..b28a3bf273ebf2d7ab124e2814ae27abf42f8842 100644
--- a/chrome/browser/ui/browser_instant_controller.h
+++ b/chrome/browser/ui/browser_instant_controller.h
@@ -63,6 +63,9 @@ class BrowserInstantController : public content::NotificationObserver,
   // to the user clicking on it.
   void InstantPreviewFocused();
 
+  // Invoked by |instant_| to set invisible focus in the omnibox.
+  void SetInvisibleFocus();

[Peter Kasting, 2012/12/04 02:00:52]

Nit: Maybe this should be:

  // Invoked by |instant_| to give the omnibox focus invisibly.
  void FocusOmniboxInvisibly();

...since we're not really setting anything on the controller per se.

[samarth, 2012/12/04 04:55:35]

Done.

+
   // Invoked by |instant_| to get the currently active tab, over which the
   // preview would be shown.
   TabContents* GetActiveTabContents() const;