Migrate WebGL contexts on backgrounded tabs to the integrated GPU.

ui/gl/gl_context.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_context.h"
 
 #include <string>
 
 #include "base/bind.h"
 #include "base/cancelable_callback.h"
@@ skipping 79 matching lines @@
   DCHECK(IsCurrent(nullptr));
   const char *renderer =
       reinterpret_cast<const char*>(glGetString(GL_RENDERER));
   return std::string(renderer ? renderer : "");
 }
 
 YUVToRGBConverter* GLContext::GetYUVToRGBConverter() {
   return nullptr;
 }
 
+void GLContext::SetPerformancePreference(GpuPerformancePreference pref) {
+}
+
 bool GLContext::HasExtension(const char* name) {
   std::string extensions = GetExtensions();
   extensions += " ";
 
   std::string delimited_name(name);
   delimited_name += " ";
 
   return extensions.find(delimited_name) != std::string::npos;
 }
 
@@ skipping 163 matching lines @@
 
 scoped_refptr<GLContext> InitializeGLContext(scoped_refptr<GLContext> context,
                                              GLSurface* compatible_surface,
                                              const GLContextAttribs& attribs) {
   if (!context->Initialize(compatible_surface, attribs))
     return nullptr;
   return context;
 }
 
 }  // namespace gl