add previously focused node to WebClient::focusedNodeChanged

public/web/WebViewClient.h

 /*
  * Copyright (C) 2009 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 168 matching lines @@
 
     // Called to determine if drag-n-drop operations may initiate a page
     // navigation.
     virtual bool acceptsLoadDrops() { return true; }
 
     // Take focus away from the WebView by focusing an adjacent UI element
     // in the containing window.
     virtual void focusNext() { }
     virtual void focusPrevious() { }
 
-    // Called when a new node gets focused.
+    // FIXME: remove this function.
     virtual void focusedNodeChanged(const WebNode&) { }
+    // Called when a new node gets focused. |fromNode| is the previously focused node, |toNode|
+    // is the newly focused node. Either can be null.
+    virtual void focusedNodeChanged(const WebNode& fromNode, const WebNode& toNode) { }
 
     // Indicates two things:
     //   1) This view may have a new layout now.
     //   2) Calling layout() is a no-op.
     // After calling WebWidget::layout(), expect to get this notification
     // unless the view did not need a layout.
     virtual void didUpdateLayout() { }
 
     // Return true to swallow the input event if the embedder will start a disambiguation popup
     virtual bool didTapMultipleTargets(const WebSize& pinchViewportOffset, const WebRect& touchRect, const WebVector<WebRect>& targetRects) { return false; }
@@ skipping 92 matching lines @@
     // Informs the browser that the draggable regions have been updated.
     virtual void draggableRegionsChanged() { }
 
 protected:
     ~WebViewClient() { }
 };
 
 } // namespace blink
 
 #endif