Add a flag use_software_compositing to the Widget::InitParams structure.

ui/views/controls/menu/menu_host.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 "ui/views/controls/menu/menu_host.h"
 
 #include "base/auto_reset.h"
 #include "base/trace_event/trace_event.h"
 #include "ui/events/gestures/gesture_recognizer.h"
 #include "ui/gfx/path.h"
@@ skipping 34 matching lines @@
   bool rounded_border = menu_controller && menu_config.corner_radius > 0;
   bool bubble_border = submenu_->GetScrollViewContainer() &&
                        submenu_->GetScrollViewContainer()->HasBubbleBorder();
   params.shadow_type = bubble_border ? Widget::InitParams::SHADOW_TYPE_NONE
                                      : Widget::InitParams::SHADOW_TYPE_DROP;
   params.opacity = (bubble_border || rounded_border) ?
       Widget::InitParams::TRANSLUCENT_WINDOW :
       Widget::InitParams::OPAQUE_WINDOW;
   params.parent = parent ? parent->GetNativeView() : NULL;
   params.bounds = bounds;
+#if defined(OS_WIN)
+  // On Windows use the software compositor to ensure that we don't block
+  // the UI thread blocking issue during command buffer creation. We can
+  // revert this change once http://crbug.com/125248 is fixed.
+  params.force_software_compositing = true;
+#endif
   Init(params);
 
   SetContentsView(contents_view);
   ShowMenuHost(do_capture);
 }
 
 bool MenuHost::IsMenuHostVisible() {
   return IsVisible();
 }
 
@@ skipping 94 matching lines @@
   }
   menu_controller->OnDragComplete(should_close);
 
   // We may have lost capture in the drag and drop, but are remaining open.
   // Return capture so we get MouseCaptureLost events.
   if (!should_close)
     native_widget_private()->SetCapture();
 }
 
 }  // namespace views