Mac: Correctly show/hide compositor on navigations.

chrome/browser/renderer_host/render_widget_host.cc

 // Copyright (c) 2010 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 "chrome/browser/renderer_host/render_widget_host.h"
 
 #include "base/auto_reset.h"
 #include "base/command_line.h"
 #include "base/histogram.h"
 #include "base/keyboard_codes.h"
@@ skipping 902 matching lines @@
   if (view_)
     view_->ImeUpdateTextInputState(type, caret_rect);
 }
 
 void RenderWidgetHost::OnMsgImeCancelComposition() {
   if (view_)
     view_->ImeCancelComposition();
 }
 
 void RenderWidgetHost::OnMsgGpuRenderingActivated(bool activated) {
+#if defined(OS_MACOSX)
+  bool old_state = is_gpu_rendering_active_;
+#endif
   is_gpu_rendering_active_ = activated;
+#if defined(OS_MACOSX)
+  if (old_state != is_gpu_rendering_active_ && view_)
+    view_->GpuRenderingStateDidChange();
+#endif
 }
 
 #if defined(OS_MACOSX)
 
 void RenderWidgetHost::OnMsgShowPopup(
     const ViewHostMsg_ShowPopup_Params& params) {
   view_->ShowPopupWithItems(params.bounds,
                             params.item_height,
                             params.item_font_size,
                             params.selected_item,
@@ skipping 241 matching lines @@
     // of this key event.
     if (!processed && !is_hidden_ && !front_item.skip_in_browser) {
       UnhandledKeyboardEvent(front_item);
 
       // WARNING: This RenderWidgetHost can be deallocated at this point
       // (i.e.  in the case of Ctrl+W, where the call to
       // UnhandledKeyboardEvent destroys this RenderWidgetHost).
     }
   }
 }