gpu: Fix corrupted state due to virtual MakeCurrent race.

ui/gl/gl_gl_api_implementation.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 "ui/gl/gl_gl_api_implementation.h"
 
 #include <algorithm>
 #include <vector>
 
 #include "base/command_line.h"
@@ skipping 267 matching lines @@
     DCHECK_EQ(glGetErrorFn(), static_cast<GLenum>(GL_NO_ERROR));
 
     current_context_ = virtual_context;
     // Set all state that is different from the real state
     // NOTE: !!! This is a temporary implementation that just restores all
     // state to let us test that it works.
     // TODO: ASAP, change this to something that only restores the state
     // needed for individual GL calls.
     GLApi* temp = GetCurrentGLApi();
     SetGLToRealGLApi();
-    virtual_context->GetGLStateRestorer()->RestoreState();
+    if (virtual_context->GetGLStateRestorer()->IsInitialized())
+      virtual_context->GetGLStateRestorer()->RestoreState();
     SetGLApi(temp);
   }
   SetGLApi(this);
   return true;
 }
 
 void VirtualGLApi::OnDestroyVirtualContext(GLContext* virtual_context) {
   if (current_context_ == virtual_context)
     current_context_ = NULL;
 }
 
 const GLubyte* VirtualGLApi::glGetStringFn(GLenum name) {
   switch (name) {
     case GL_EXTENSIONS:
       return reinterpret_cast<const GLubyte*>(extensions_.c_str());
     default:
       return driver_->fn.glGetStringFn(name);
   }
 }
 
 }  // namespace gfx