Warm up DWM prior to lowering token.

content/gpu/gpu_main.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 <stdlib.h>
 
 #if defined(OS_WIN)
+#include <dwmapi.h>
 #include <windows.h>
 #endif
 
 #include "base/debug/trace_event.h"
 #include "base/lazy_instance.h"
 #include "base/message_loop/message_loop.h"
 #include "base/rand_util.h"
 #include "base/strings/string_number_conversions.h"
 #include "base/strings/stringprintf.h"
 #include "base/threading/platform_thread.h"
@@ skipping 10 matching lines @@
 #include "content/public/common/content_switches.h"
 #include "content/public/common/main_function_params.h"
 #include "crypto/hmac.h"
 #include "gpu/config/gpu_info_collector.h"
 #include "ui/gl/gl_implementation.h"
 #include "ui/gl/gl_surface.h"
 #include "ui/gl/gl_switches.h"
 #include "ui/gl/gpu_switching_manager.h"
 
 #if defined(OS_WIN)
+#include "base/win/windows_version.h"
 #include "base/win/scoped_com_initializer.h"
 #include "content/common/gpu/media/dxva_video_decode_accelerator.h"
 #include "sandbox/win/src/sandbox.h"
 #elif defined(OS_CHROMEOS) && defined(ARCH_CPU_ARMEL) && defined(USE_X11)
 #include "content/common/gpu/media/exynos_video_decode_accelerator.h"
 #elif defined(OS_CHROMEOS) && defined(ARCH_CPU_X86_FAMILY) && defined(USE_X11)
 #include "content/common/gpu/media/vaapi_wrapper.h"
 #endif
 
 #if defined(USE_X11)
@@ skipping 320 matching lines @@
       LOG(ERROR) << "WarmUpSandbox() failed with loading setupapi.dll";
       return false;
     }
   }
 
   if (!command_line.HasSwitch(switches::kDisableAcceleratedVideoDecode)) {
     TRACE_EVENT0("gpu", "Initialize DXVA");
     // Initialize H/W video decoding stuff which fails in the sandbox.
     DXVAVideoDecodeAccelerator::PreSandboxInitialization();
   }
+
+  {
+    TRACE_EVENT0("gpu", "Warm up DWM");
+
+    // DWM was introduced with Windows Vista. DwmFlush seems to be sufficient
+    // to warm it up before lowering the token. DWM is required to present to
+    // a window with Vista and later and this allows us to do so with the
+    // GPU process sandbox enabled.
+    if (base::win::GetVersion() >= base::win::VERSION_VISTA) {
+      HMODULE module = LoadLibrary(L"dwmapi.dll");
+      if (module) {
+        typedef HRESULT (WINAPI *DwmFlushFunc)();
+        DwmFlushFunc dwm_flush = reinterpret_cast<DwmFlushFunc>(
+            GetProcAddress(module, "DwmFlush"));
+        if (dwm_flush)
+          dwm_flush();
+      }
+    }
+  }
 #endif
   return true;
 }
 
 #if defined(OS_LINUX)
 void WarmUpSandboxNvidia(const gpu::GPUInfo& gpu_info,
                          bool should_initialize_gl_context) {
   // We special case Optimus since the vendor_id we see may not be Nvidia.
   bool uses_nvidia_driver = (gpu_info.gpu.vendor_id == 0x10de &&  // NVIDIA.
                              gpu_info.driver_vendor == "NVIDIA") ||
@@ skipping 38 matching lines @@
     return true;
   }
 
   return false;
 }
 #endif  // defined(OS_WIN)
 
 }  // namespace.
 
 }  // namespace content