Add zoom extension API

chrome/browser/host_zoom_map.h

Index: chrome/browser/host_zoom_map.h
diff --git a/chrome/browser/host_zoom_map.h b/chrome/browser/host_zoom_map.h
index 85e02edcd0a78759285b697aae2160ac7f630947..ba318c088b0003ec56dfa9f7d32ef52644dbfbf8 100644
--- a/chrome/browser/host_zoom_map.h
+++ b/chrome/browser/host_zoom_map.h
@@ -50,7 +50,7 @@ class HostZoomMap :
   // otherwise the new value is written out.
   //
   // This should only be called on the UI thread.
-  void SetZoomLevel(const GURL& url, double level);
+  void SetZoomLevel(const GURL& url, int request_id, double level);
 
   // Returns the temporary zoom level that's only valid for the lifetime of
   // the given tab (i.e. isn't saved and doesn't affect other tabs) if it
@@ -66,6 +66,7 @@ class HostZoomMap :
   // This should only be called on the UI thread.
   void SetTemporaryZoomLevel(int render_process_id,
                              int render_view_id,
+                             int request_id,
                              double level);
 
   // Resets all zoom levels.