Move didChangeSelection to WebFrameClient.

public/web/WebFrameClient.h

 /*
  * Copyright (C) 2011, 2012 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 206 matching lines @@
     // The navigation resulted in no change to the documents within the page.
     // For example, the navigation may have just resulted in scrolling to a
     // named anchor or a PopState event may have been dispatched.
     virtual void didNavigateWithinPage(WebFrame*, bool isNewNavigation) { }
 
     // Called upon update to scroll position, document state, and other
     // non-navigational events related to the data held by WebHistoryItem.
     // WARNING: This method may be called very frequently.
     virtual void didUpdateCurrentHistoryItem(WebFrame*) { }
 
+    // Editing -------------------------------------------------------------
+
+    // These methods allow the client to intercept and overrule editing
+    // operations.
+    virtual void didChangeSelection(bool isSelectionEmpty) { }
+
 
     // UI ------------------------------------------------------------------
 
     // Shows a context menu with commands relevant to a specific element on
     // the given frame. Additional context data is supplied.
     virtual void showContextMenu(const WebContextMenuData&) { }
 
     // Called when the data attached to the currently displayed context menu is
     // invalidated. The context menu may be closed if possible.
     virtual void clearContextMenu() { }
@@ skipping 156 matching lines @@
     // Send initial drawing parameters to a child frame that is being rendered out of process.
     virtual void initializeChildFrame(const WebRect& frameRect, float scaleFactor) { }
 
 protected:
     ~WebFrameClient() { }
 };
 
 } // namespace blink
 
 #endif