Mac ÜC: Fix white page hangs

content/browser/gpu/gpu_process_host.cc

Index: content/browser/gpu/gpu_process_host.cc
diff --git a/content/browser/gpu/gpu_process_host.cc b/content/browser/gpu/gpu_process_host.cc
index a7c3aa703d3acd057cb54484394b309f3a7b6f72..d4a89662d008c30a3e5183774cb46746df1de41a 100644
--- a/content/browser/gpu/gpu_process_host.cc
+++ b/content/browser/gpu/gpu_process_host.cc
@@ -903,6 +903,8 @@ void GpuProcessHost::OnAcceleratedSurfaceBuffersSwapped(
   // RenderWidgetHostImpl.
   ViewHostMsg_CompositorSurfaceBuffersSwapped_Params view_params;
   view_params.use_native_widget = native_widget;
+  view_params.native_widget_token = native_widget ?
+      RenderWidgetHelper::CreateNativeWidgetSwapToken() : 0;
   view_params.surface_id = params.surface_id;
   view_params.surface_handle = params.surface_handle;
   view_params.route_id = params.route_id;
@@ -910,18 +912,22 @@ void GpuProcessHost::OnAcceleratedSurfaceBuffersSwapped(
   view_params.scale_factor = params.scale_factor;
   view_params.gpu_process_host_id = host_id_;
   view_params.latency_info = params.latency_info;
-  if (helper) {
-    helper->DidReceiveBackingStoreMsg(
-        ViewHostMsg_CompositorSurfaceBuffersSwapped(
-            render_widget_id,
-            view_params));
-  } else if (native_widget) {
+  // Always post a task to handle native widget messages, in case the helper
+  // that the message is sent to is destroyed before the message is handled.
+  if (native_widget) {
     BrowserThread::PostTask(
         BrowserThread::UI,
         FROM_HERE,
         base::Bind(&RenderWidgetHelper::OnNativeSurfaceBuffersSwappedOnUIThread,
                        view_params));
   }
+  if (helper) {
+    helper->DidReceiveBackingStoreMsg(
+        ViewHostMsg_CompositorSurfaceBuffersSwapped(
+            render_widget_id,
+            view_params));
+  }
+
 }
 #endif  // OS_MACOSX