Fixes info bubble painting bug. This was happening because we were...

chrome/views/widget_win.h

 // Copyright (c) 2006-2008 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_VIEWS_WIDGET_WIN_H_
 #define CHROME_VIEWS_WIDGET_WIN_H_
 
 #include <atlbase.h>
 #include <atlcrack.h>
 
@@ skipping 114 matching lines @@
   UINT initial_class_style() { return class_style_; }
 
   void set_delete_on_destroy(bool delete_on_destroy) {
     delete_on_destroy_ = delete_on_destroy;
   }
 
   // Sets the initial opacity of a layered window, or updates the window's
   // opacity if it is on the screen.
   void SetLayeredAlpha(BYTE layered_alpha);
 
+  // See description of use_layered_buffer_ for details.
+  void SetUseLayeredBuffer(bool use_layered_buffer);
+
   // Disable Layered Window updates by setting to false.
   void set_can_update_layered_window(bool can_update_layered_window) {
     can_update_layered_window_ = can_update_layered_window;
   }
 
   // Returns the RootView associated with the specified HWND (if any).
   static RootView* FindRootView(HWND hwnd);
 
   // Closes the window asynchronously by scheduling a task for it.  The window
   // is destroyed as a result.
@@ skipping 397 matching lines @@
 
   // Window Styles used when creating the window.
   DWORD window_style_;
 
   // Window Extended Styles used when creating the window.
   DWORD window_ex_style_;
 
   // Style of the class to use.
   UINT class_style_;
 
-  // Whether or not this is a layered window.
-  bool layered_;
+  // Should we keep an offscreen buffer? This is initially true and if the
+  // window has WS_EX_LAYERED then it remains true. You can set this to false
+  // at any time to ditch the buffer, and similarly set back to true to force
+  // creation of the buffer.
+  //
+  // NOTE: this is intended to be used with a layered window (a window with an
+  // extended window style of WS_EX_LAYERED). If you are using a layered window
+  // and NOT changing the layered alpha or anything else, then leave this value
+  // alone. OTOH if you are invoking SetLayeredWindowAttributes then you'll
+  // must likely want to set this to false, or after changing the alpha toggle
+  // the extended style bit to false than back to true. See MSDN for more
+  // details.
+  bool use_layered_buffer_;
 
   // The default alpha to be applied to the layered window.
   BYTE layered_alpha_;
 
   // A canvas that contains the window contents in the case of a layered
   // window.
   scoped_ptr<ChromeCanvas> contents_;
 
   // Whether or not the window should delete itself when it is destroyed.
   // Set this to false via its setter for stack allocated instances.
@@ skipping 18 matching lines @@
   CComPtr<IAccessible> accessibility_root_;
 
   // Our hwnd.
   HWND hwnd_;
 };
 
 }  // namespace views
 
 #endif  // #ifndef CHROME_VIEWS_WIDGET_WIN_H_