Fix the race condition between mac drawRect and toggling accelerated compositing

content/browser/renderer_host/render_widget_host_view_mac.mm

 // Copyright (c) 2011 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_mac.h"
 
 #include <QuartzCore/QuartzCore.h>
 
 #include "base/bind.h"
 #include "base/debug/trace_event.h"
@@ skipping 208 matching lines @@
   *results = WebKit::WebScreenInfoFactory::screenInfo(NULL);
 }
 
 ///////////////////////////////////////////////////////////////////////////////
 // RenderWidgetHostViewMac, public:
 
 RenderWidgetHostViewMac::RenderWidgetHostViewMac(RenderWidgetHost* widget)
     : render_widget_host_(widget),
       about_to_validate_and_paint_(false),
       call_set_needs_display_in_rect_pending_(false),
+      last_frame_was_accelerated_(false),
       text_input_type_(ui::TEXT_INPUT_TYPE_NONE),
       is_loading_(false),
       is_hidden_(false),
       is_showing_context_menu_(false),
       weak_factory_(this),
       accelerated_compositing_active_(false),
       needs_gpu_visibility_update_after_repaint_(false),
       compositing_surface_(gfx::kNullPluginWindow) {
   // |cocoa_view_| owns us and we will be deleted when |cocoa_view_| goes away.
   // Since we autorelease it, our caller must put |native_view()| into the view
@@ skipping 292 matching lines @@
 void RenderWidgetHostViewMac::ImeCompositionRangeChanged(
     const ui::Range& range) {
   // The RangeChanged message is only sent with valid values. The current
   // caret position (start == end) will be sent if there is no IME range.
   [cocoa_view_ setMarkedRange:range.ToNSRange()];
 }
 
 void RenderWidgetHostViewMac::DidUpdateBackingStore(
     const gfx::Rect& scroll_rect, int scroll_dx, int scroll_dy,
     const std::vector<gfx::Rect>& copy_rects) {
+  last_frame_was_accelerated_ = false;
+
   if (!is_hidden_) {
     std::vector<gfx::Rect> rects(copy_rects);
 
     // Because the findbar might be open, we cannot use scrollRect:by: here. For
     // now, simply mark all of scroll rect as dirty.
     if (!scroll_rect.IsEmpty())
       rects.push_back(scroll_rect);
 
     for (size_t i = 0; i < rects.size(); ++i) {
       NSRect ns_rect = [cocoa_view_ flipRectToNSRect:rects[i]];
@@ skipping 318 matching lines @@
     uint64 surface_id,
     int renderer_id,
     int32 route_id,
     int gpu_host_id) {
   TRACE_EVENT0("browser",
       "RenderWidgetHostViewMac::AcceleratedSurfaceBuffersSwapped");
   CHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
   AcceleratedPluginView* view = ViewForPluginWindowHandle(window);
   DCHECK(view);
   if (view) {
+    last_frame_was_accelerated_ = true;
     plugin_container_manager_.SetSurfaceWasPaintedTo(window, surface_id);
 
     // The surface is hidden until its first paint, to not show gargabe.
     if (plugin_container_manager_.SurfaceShouldBeVisible(window))
       [view setHidden:NO];
     [view drawView];
   }
 
   if (renderer_id != 0 || route_id != 0) {
     AcknowledgeSwapBuffers(renderer_id,
@@ skipping 842 matching lines @@
 - (void)drawRect:(NSRect)dirtyRect {
   if (!renderWidgetHostView_->render_widget_host_) {
     // TODO(shess): Consider using something more noticable?
     [[NSColor whiteColor] set];
     NSRectFill(dirtyRect);
     return;
   }
 
   const gfx::Rect damagedRect([self flipNSRectToRect:dirtyRect]);
 
-  if (renderWidgetHostView_->render_widget_host_->
-      is_accelerated_compositing_active()) {
+  if (renderWidgetHostView_->last_frame_was_accelerated_) {
     gfx::Rect gpuRect;
 
     gfx::PluginWindowHandle root_handle =
        renderWidgetHostView_->plugin_container_manager_.root_container_handle();
     if (root_handle != gfx::kNullPluginWindow) {
       AcceleratedPluginView* view =
           renderWidgetHostView_->ViewForPluginWindowHandle(root_handle);
       DCHECK(view);
       if (view && ![view isHidden]) {
         gpuRect = [self flipNSRectToRect:[view frame]];
@@ skipping 992 matching lines @@
   if (!string) return NO;
 
   // If the user is currently using an IME, confirm the IME input,
   // and then insert the text from the service, the same as TextEdit and Safari.
   [self confirmComposition];
   [self insertText:string];
   return YES;
 }
 
 @end