Drop accelerated surface when switching off accelerated compositor.

content/browser/renderer_host/render_widget_host_view_win.cc

 // 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.
 
 #include "content/browser/renderer_host/render_widget_host_view_win.h"
 
 #include <algorithm>
 #include <peninputpanel_i.c>
 
 #include "base/bind.h"
@@ skipping 2119 matching lines @@
     for (size_t i = 0; i < plugin_windows.size(); ++i) {
       HWND next;
       if (i + 1 < plugin_windows.size())
         next = plugin_windows[i+1];
       else
         next = compositor_host_window_;
       ::SetWindowPos(plugin_windows[i], next, 0, 0, 0, 0,
           SWP_NOSIZE | SWP_NOMOVE | SWP_NOACTIVATE);
     }
   } else {
+    // Drop the backing store for the accelerated surface when the accelerated
+    // compositor is disabled. Otherwise, a flash of the last presented frame
+    // could appear when it is next enabled.
+    if (accelerated_surface_.get())
+      accelerated_surface_->Suspend();
     hide_compositor_window_at_next_paint_ = true;
   }
 }
 
 void RenderWidgetHostViewWin::AcceleratedSurfaceBuffersSwapped(
     const GpuHostMsg_AcceleratedSurfaceBuffersSwapped_Params& params,
     int gpu_host_id) {
   NOTREACHED();
 }
 
@@ skipping 449 matching lines @@
 void RenderWidgetHostViewWin::ResetPointerDownContext() {
   // If the default focus on the page is on an edit field and we did not
   // receive a focus change in the context of a pointer down message, it means
   // that the pointer down message occurred on the edit field and we should
   // display the on screen keyboard
   if (!received_focus_change_after_pointer_down_ && virtual_keyboard_)
     DisplayOnScreenKeyboardIfNeeded();
   received_focus_change_after_pointer_down_ = false;
   pointer_down_context_ = false;
 }