Allow Windows to use system Vsync if only one window is swapping

content/common/gpu/image_transport_surface.cc

 // Copyright (c) 2012 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/common/gpu/image_transport_surface.h"
 
 #include "base/bind.h"
 #include "base/bind_helpers.h"
 #include "base/command_line.h"
 #include "base/debug/trace_event.h"
 #include "content/common/gpu/gpu_channel.h"
 #include "content/common/gpu/gpu_channel_manager.h"
 #include "content/common/gpu/gpu_command_buffer_stub.h"
 #include "content/common/gpu/gpu_messages.h"
 #include "content/common/gpu/null_transport_surface.h"
 #include "gpu/command_buffer/service/gpu_scheduler.h"
 #include "gpu/command_buffer/service/sync_point_manager.h"
 #include "ui/gfx/vsync_provider.h"
 #include "ui/gl/gl_implementation.h"
 #include "ui/gl/gl_switches.h"
 
-#if defined(OS_WIN)
-#include "ui/base/win/shell.h"
-#endif
-
 namespace content {
 
 ImageTransportSurface::ImageTransportSurface() {}
 
 ImageTransportSurface::~ImageTransportSurface() {}
 
 scoped_refptr<gfx::GLSurface> ImageTransportSurface::CreateSurface(
     GpuChannelManager* manager,
     GpuCommandBufferStub* stub,
     const gfx::GLSurfaceHandle& handle) {
@@ skipping 110 matching lines @@
 }
 
 bool ImageTransportHelper::MakeCurrent() {
   gpu::gles2::GLES2Decoder* decoder = Decoder();
   if (!decoder)
     return false;
   return decoder->MakeCurrent();
 }
 
 void ImageTransportHelper::SetSwapInterval(gfx::GLContext* context) {
-#if defined(OS_WIN)
-  // If Aero Glass is enabled, then the renderer will handle ratelimiting and
-  // there's no tearing, so waiting for vsync is unnecessary.
-  if (ui::win::IsAeroGlassEnabled()) {
-    context->SetSwapInterval(0);
-    return;
-  }
-#endif
   if (CommandLine::ForCurrentProcess()->HasSwitch(switches::kDisableGpuVsync))
     context->SetSwapInterval(0);
   else
     context->SetSwapInterval(1);
 }
 
 gpu::GpuScheduler* ImageTransportHelper::Scheduler() {
   if (!stub_.get())
     return NULL;
   return stub_->scheduler();
@@ skipping 123 matching lines @@
 void PassThroughImageTransportSurface::SendVSyncUpdateIfAvailable() {
   gfx::VSyncProvider* vsync_provider = GetVSyncProvider();
   if (vsync_provider) {
     vsync_provider->GetVSyncParameters(
       base::Bind(&ImageTransportHelper::SendUpdateVSyncParameters,
                  helper_->AsWeakPtr()));
   }
 }
 
 }  // namespace content