GTK Render Widget Host View resets cached center location on mouse lock.

content/browser/renderer_host/render_widget_host_view_gtk.h

 // Copyright (c) 2012 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 CONTENT_BROWSER_RENDERER_HOST_RENDER_WIDGET_HOST_VIEW_GTK_H_
 #define CONTENT_BROWSER_RENDERER_HOST_RENDER_WIDGET_HOST_VIEW_GTK_H_
 #pragma once
 
 #include <gdk/gdk.h>
 
@@ skipping 182 matching lines @@
 
   // Do initialization needed just by InitAsPopup() and InitAsFullscreen().
   // We move and resize |window| to |bounds| and show it and its contents.
   void DoPopupOrFullscreenInit(GtkWindow* window, const gfx::Rect& bounds);
 
   // Update the display cursor for the render view.
   void ShowCurrentCursor();
 
   void set_last_mouse_down(GdkEventButton* event);
 
+  // Cause the next query for the widget center to recompute the cached value.
+  void MarkCachedWidgetCenterStale();
+
   gfx::Point GetWidgetCenter();
 
   // The model object.
   content::RenderWidgetHostImpl* host_;
 
   // The native UI widget.
   ui::OwnedWidgetGtk view_;
 
   // This is true when we are currently painting and thus should handle extra
   // paint requests by expanding the invalid rect rather than actually
@@ skipping 91 matching lines @@
   GdkEventButton* last_mouse_down_;
 
   // Instance of accessibility information for the root of the AtkObject
   // tree representation of the WebKit render tree.
   scoped_ptr<BrowserAccessibilityManager> browser_accessibility_manager_;
 
   ui::GtkSignalRegistrar signals_;
 };
 
 #endif  // CHROME_BROWSER_RENDERER_HOST_RENDER_WIDGET_HOST_VIEW_GTK_H_