Allow GraphicsContext3D to be created with a NULL WebView for offscreen

webkit/gpu/webgraphicscontext3d_in_process_command_buffer_impl.cc

 // Copyright (c) 2011 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.
 
 #if defined(ENABLE_GPU)
 
 #include "webkit/gpu/webgraphicscontext3d_in_process_command_buffer_impl.h"
 
 #include <GLES2/gl2.h>
 #ifndef GL_GLEXT_PROTOTYPES
@@ skipping 631 matching lines @@
   const char* preferred_extensions = attributes.noExtensions ?
       kWebGLPreferredGLExtensions : "*";
 
   GURL active_url;
   if (web_view && web_view->mainFrame())
     active_url = GURL(web_view->mainFrame()->document().url());
 
   GLInProcessContext* parent_context = NULL;
   if (!render_directly_to_web_view) {
     WebKit::WebGraphicsContext3D* view_context =
-        web_view->graphicsContext3D();
+        web_view ? web_view->graphicsContext3D() : NULL;
     if (view_context) {
       WebGraphicsContext3DInProcessCommandBufferImpl* context_impl =
           static_cast<WebGraphicsContext3DInProcessCommandBufferImpl*>(
               view_context);
       parent_context = context_impl->context_;
     }
   }
 
   // HACK: Assume this is a WebGL context by looking for the noExtensions
   // attribute. WebGL contexts must not go in the share group because they
@@ skipping 966 matching lines @@
   if (context_lost_callback_) {
     context_lost_callback_->onContextLost();
   }
 }
 
 }  // namespace gpu
 }  // namespace webkit
 
 #endif  // defined(ENABLE_GPU)