Some improvement of validation message bubble UI.

chrome/browser/ui/validation_message_bubble.h

 // Copyright (c) 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CHROME_BROWSER_UI_VALIDATION_MESSAGE_BUBBLE_H_
 #define CHROME_BROWSER_UI_VALIDATION_MESSAGE_BUBBLE_H_
 
 #include "base/memory/scoped_ptr.h"
 #include "base/strings/string16.h"
 
 namespace content {
 class RenderWidgetHost;
 }
 
 namespace gfx {
 class Rect;
 }
 
 namespace chrome {
 
 class ValidationMessageBubble {
  public:
   // Open a tooltip-like window to show the specified messages.  The window
   // should not change focus state.
   static scoped_ptr<ValidationMessageBubble> CreateAndShow(
       content::RenderWidgetHost* widget_host,
-      const gfx::Rect& anchor_in_screen,
+      const gfx::Rect& anchor_in_root_view,
       const string16& main_text,
       const string16& sub_text);
 
   // Close the window and destruct the object.
   virtual ~ValidationMessageBubble() {}
+
+  // Move the window to a position such that the bubble arrow points to the
+  // specified anchor.  |anchor_in_root_view| is in DIP unit, and relative to
+  // RWHV for |widget_host|.
+  virtual void SetPositionRelativeToAnchor(
+      content::RenderWidgetHost* widget_host,
+      const gfx::Rect& anchor_in_root_view) = 0;
 };
 
 }  // namespace chrome
 
 #endif  // CHROME_BROWSER_UI_VALIDATION_MESSAGE_BUBBLE_H_