Improve GL helpers.

mojo/gpu/gl_context_owner.cc

 // Copyright 2014 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 "mojo/gpu/gl_context_owner.h"
 
 #include "mojo/gpu/gl_context.h"
 
 namespace mojo {
 
-GLContextOwner::GLContextOwner(mojo::Shell* shell)
-    : context_(mojo::GLContext::Create(shell)) {
-}
+GLContextOwner::GLContextOwner(ApplicationConnector* connector)
+    : context_(GLContext::CreateOffscreen(connector)) {}
 
 GLContextOwner::~GLContextOwner() {
   context_->Destroy();
 }
 
 }  // namespace mojo