Do DXVA pre-sandbox initialization off the main thread.

content/gpu/gpu_main.cc

Index: content/gpu/gpu_main.cc
===================================================================
--- content/gpu/gpu_main.cc	(revision 169901)
+++ content/gpu/gpu_main.cc	(working copy)
@@ -168,6 +168,15 @@
       command_line.GetSwitchValueASCII(switches::kGpuDriverVersion);
   GetContentClient()->SetGpuInfo(gpu_info);
 
+#if defined(OS_WIN)
+  // Asynchronously initialize DXVA while GL is being initialized because
+  // they both take tens of ms.
+  base::WaitableEvent dxva_initialized(true, false);
+  DXVAVideoDecodeAccelerator::PreSandboxInitialization(
+      base::Bind(&base::WaitableEvent::Signal,
+                 base::Unretained(&dxva_initialized)));
+#endif
+
   // We need to track that information for the WarmUpSandbox function.
   bool initialized_gl_context = false;
   // Load and initialize the GL implementation and locate the GL entry points.
@@ -243,6 +252,12 @@
 
 #if defined(OS_WIN)
   {
+    // DXVA initialization must have completed before the token is lowered.
+    TRACE_EVENT0("gpu", "Wait for DXVA initialization");
+    dxva_initialized.Wait();
+  }
+
+  {
     TRACE_EVENT0("gpu", "Lower token");
     // For windows, if the target_services interface is not zero, the process
     // is sandboxed and we must call LowerToken() before rendering untrusted
@@ -342,22 +357,8 @@
 #endif
 
 #if defined(OS_WIN)
-  {
-    TRACE_EVENT0("gpu", "Initialize COM");
-    base::win::ScopedCOMInitializer com_initializer;

[apatrick_chromium, 2012/11/29 21:54:58]

This was clearly nonsense. COM would be uninitialized as soon as the variable
went out of scope.

-  }
-
-  {
-    TRACE_EVENT0("gpu", "Preload setupapi.dll");
-    // Preload this DLL because the sandbox prevents it from loading.
-    LoadLibrary(L"setupapi.dll");
-  }
-
-  {
-    TRACE_EVENT0("gpu", "Initialize DXVA");
-    // Initialize H/W video decoding stuff which fails in the sandbox.
-    DXVAVideoDecodeAccelerator::PreSandboxInitialization();
-  }
+  // Preload these DLL because the sandbox prevents them from loading.
+  LoadLibrary(L"setupapi.dll");
 #endif
 }