Mac ÜC: Fix white page hangs

content/browser/renderer_host/render_widget_helper_mac.mm

 // Copyright 2014 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_helper.h"
 
 #import <Cocoa/Cocoa.h>
 #include <IOSurface/IOSurfaceAPI.h>
 
 #include "base/bind.h"
 #include "base/lazy_instance.h"
 #include "base/synchronization/lock.h"
 #include "content/browser/compositor/browser_compositor_view_mac.h"
 #include "content/browser/gpu/gpu_process_host.h"
 #include "content/browser/gpu/gpu_surface_tracker.h"
 #include "content/common/gpu/gpu_messages.h"
 #include "content/common/gpu/surface_handle_types_mac.h"
 #include "content/common/view_messages.h"
 
 namespace content {
 namespace {
 typedef std::map<gfx::AcceleratedWidget,std::pair<int,int>> WidgetMap;
 base::LazyInstance<WidgetMap> g_widget_map;
-base::LazyInstance<base::Lock> g_lock;
+base::LazyInstance<base::Lock> g_widget_map_lock;
+
+typedef std::set<uint64> TokenSet;
+base::LazyInstance<TokenSet> g_token_set;
+uint64 g_token_last_issued = 0;
+base::LazyInstance<base::Lock> g_token_set_lock;
 }  // namespace
 
 // static
 void RenderWidgetHelper::SetRenderWidgetIDForWidget(
     gfx::AcceleratedWidget native_widget,
     int render_process_id,
     int render_widget_id) {
-  base::AutoLock lock(g_lock.Get());
+  base::AutoLock lock(g_widget_map_lock.Get());
   g_widget_map.Get()[native_widget] = std::make_pair(
       render_process_id, render_widget_id);
 }
 
 // static
 void RenderWidgetHelper::ResetRenderWidgetIDForWidget(
     gfx::AcceleratedWidget native_widget) {
-  base::AutoLock lock(g_lock.Get());
+  base::AutoLock lock(g_widget_map_lock.Get());
   g_widget_map.Get().erase(native_widget);
 }
 
 // static
 bool RenderWidgetHelper::GetRenderWidgetIDForWidget(
     gfx::AcceleratedWidget native_widget,
     int* render_process_id,
     int* render_widget_id) {
-  base::AutoLock lock(g_lock.Get());
+  base::AutoLock lock(g_widget_map_lock.Get());
 
   auto found = g_widget_map.Get().find(native_widget);
   if (found != g_widget_map.Get().end()) {
     *render_process_id = found->second.first;
     *render_widget_id = found->second.second;
     return true;
   }
 
   *render_process_id = 0;
   *render_widget_id = 0;
   return false;
 }
 
+uint64 RenderWidgetHelper::CreateNativeWidgetSwapToken() {
+  base::AutoLock lock(g_token_set_lock.Get());
+  g_token_last_issued += 1;
+  g_token_set.Get().insert(g_token_last_issued);
+  return g_token_last_issued;
+}
+
 // static
 void RenderWidgetHelper::OnNativeSurfaceBuffersSwappedOnUIThread(
     const ViewHostMsg_CompositorSurfaceBuffersSwapped_Params& params) {
+  {
+    base::AutoLock lock(g_token_set_lock.Get());
+    auto found = g_token_set.Get().find(params.native_widget_token);
+    if (found == g_token_set.Get().end())
+      return;
+    g_token_set.Get().erase(found);
+  }
+
   DCHECK(content::BrowserThread::CurrentlyOn(content::BrowserThread::UI));
   gfx::AcceleratedWidget native_widget =
       content::GpuSurfaceTracker::Get()->AcquireNativeWidget(params.surface_id);
   IOSurfaceID io_surface_id = content::IOSurfaceIDFromSurfaceHandle(
       params.surface_handle);
   [native_widget gotAcceleratedIOSurfaceFrame:io_surface_id
                           withOutputSurfaceID:params.surface_id
                               withLatencyInfo:params.latency_info
                                 withPixelSize:params.size
                               withScaleFactor:params.scale_factor];
 }
 
 }  // namespace content