Implement client side PBOs for glReadPixel

content/browser/renderer_host/image_transport_factory.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/browser/renderer_host/image_transport_factory.h"
 
 #include <algorithm>
 #include <map>
 
 #include "base/bind.h"
@@ skipping 448 matching lines @@
         device_scale_factor,
         texture_id));
     return image;
   }
 
   virtual GLHelper* GetGLHelper() OVERRIDE {
     if (!gl_helper_.get()) {
       CreateSharedContextLazy();
       WebKit::WebGraphicsContext3D* context_for_main_thread =
           shared_contexts_main_thread_->Context3d();
-      WebKit::WebGraphicsContext3D* context_for_thread =
-          CreateOffscreenContext();
-      if (!context_for_thread)
-        return NULL;
-
-      gl_helper_.reset(new GLHelper(context_for_main_thread,
-                                    context_for_thread));
+      gl_helper_.reset(new GLHelper(context_for_main_thread));
     }
     return gl_helper_.get();
   }
 
   virtual uint32 InsertSyncPoint() OVERRIDE {
     if (!shared_contexts_main_thread_)
       return 0;
     return shared_contexts_main_thread_->Context3d()->insertSyncPoint();
   }
 
@@ skipping 280 matching lines @@
   delete g_factory;
   g_factory = NULL;
 }
 
 // static
 ImageTransportFactory* ImageTransportFactory::GetInstance() {
   return g_factory;
 }
 
 }  // namespace content