Mac: Fix flicker on gpu->nongpu transitions.

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 "app/keyboard_codes.h"
 #include "base/auto_reset.h"
 #include "base/command_line.h"
 #include "base/message_loop.h"
@@ skipping 61 matching lines @@
                                    int routing_id)
     : renderer_initialized_(false),
       renderer_accessible_(false),
       view_(NULL),
       process_(process),
       painting_observer_(NULL),
       routing_id_(routing_id),
       is_loading_(false),
       is_hidden_(false),
       is_gpu_rendering_active_(false),
+#if defined(OS_MACOSX)
+      needs_to_hide_gpu_view_on_paint_(false),
+#endif
       repaint_ack_pending_(false),
       resize_ack_pending_(false),
       mouse_move_pending_(false),
       mouse_wheel_pending_(false),
       needs_repainting_on_restore_(false),
       is_unresponsive_(false),
       in_get_backing_store_(false),
       view_being_painted_(false),
       ignore_input_events_(false),
       text_direction_updated_(false),
@@ skipping 724 matching lines @@
         // Paint the backing store. This will update it with the
         // renderer-supplied bits. The view will read out of the backing store
         // later to actually draw to the screen.
         PaintBackingStoreRect(params.bitmap, params.bitmap_rect,
                               params.copy_rects, params.view_size,
                               &painted_synchronously);
       }
     }
   }
 
+#if defined(OS_MACOSX)
+  if (needs_to_hide_gpu_view_on_paint_) {
+    if (view_)
+      view_->GpuRenderingStateDidChange();
+    needs_to_hide_gpu_view_on_paint_ = false;
+  }
+#endif
+
   // ACK early so we can prefetch the next PaintRect if there is a next one.
   // This must be done AFTER we're done painting with the bitmap supplied by the
   // renderer. This ACK is a signal to the renderer that the backing store can
   // be re-used, so the bitmap may be invalid after this call. If the backing
   // store is painting asynchronously, it will manage issuing this IPC.
   if (painted_synchronously)
     Send(new ViewMsg_UpdateRect_ACK(routing_id_));
 
   // We don't need to update the view if the view is hidden. We must do this
   // early return after the ACK is sent, however, or the renderer will not send
@@ skipping 128 matching lines @@
   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();
+  if (old_state != is_gpu_rendering_active_ && view_) {
+    if (is_gpu_rendering_active_) {
+      view_->GpuRenderingStateDidChange();
+    } else {
+      // Delay revealing the non-gpu view until it has been repainted.
+      needs_to_hide_gpu_view_on_paint_ = true;
+    }
+  }
 #endif
 }
 
 #if defined(OS_MACOSX)
 
 void RenderWidgetHost::OnMsgShowPopup(
     const ViewHostMsg_ShowPopup_Params& params) {
   view_->ShowPopupWithItems(params.bounds,
                             params.item_height,
                             params.item_font_size,
@@ skipping 239 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).
     }
   }
 }