Don't call renderView methods in threaded mode

content/renderer/gpu/webgraphicscontext3d_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 "content/renderer/gpu/webgraphicscontext3d_command_buffer_impl.h"
 
 #include "third_party/khronos/GLES2/gl2.h"
 #ifndef GL_GLEXT_PROTOTYPES
 #define GL_GLEXT_PROTOTYPES 1
 #endif
 #include "third_party/khronos/GLES2/gl2ext.h"
 
 #include <algorithm>
 #include <set>
 
 #include "base/bind.h"
 #include "base/lazy_instance.h"
 #include "base/string_tokenizer.h"
 #include "base/command_line.h"
 #include "base/debug/trace_event.h"
 #include "base/logging.h"
 #include "base/metrics/histogram.h"
 #include "base/synchronization/lock.h"
+#include "content/common/child_process.h"
 #include "content/public/common/content_switches.h"
 #include "content/renderer/gpu/command_buffer_proxy.h"
 #include "content/renderer/gpu/gpu_channel_host.h"
 #include "content/renderer/render_thread_impl.h"
 #include "content/renderer/render_view_impl.h"
 #include "gpu/command_buffer/client/gles2_implementation.h"
 #include "gpu/command_buffer/common/constants.h"
 #include "third_party/WebKit/Source/WebKit/chromium/public/WebDocument.h"
 #include "third_party/WebKit/Source/WebKit/chromium/public/WebFrame.h"
 #include "third_party/WebKit/Source/WebKit/chromium/public/WebView.h"
@@ skipping 104 matching lines @@
 }
 
 bool WebGraphicsContext3DCommandBufferImpl::MaybeInitializeGL() {
   if (context_)
     return true;
   if (initialize_failed_)
     return false;
 
   TRACE_EVENT0("gpu", "WebGfxCtx3DCmdBfrImpl::MaybeInitializeGL");
 
+  // If the context is being initialized on something other than the main
+  // thread, then drop the web_view_ pointer so we don't accidentally
+  // dereference it.
+  MessageLoop* main_message_loop =
+      ChildProcess::current()->main_thread()->message_loop();
+  if (MessageLoop::current() != main_message_loop)
+    web_view_ = NULL;
+
   // Convert WebGL context creation attributes into RendererGLContext / EGL size
   // requests.
   const int alpha_size = attributes_.alpha ? 8 : 0;
   const int depth_size = attributes_.depth ? 24 : 0;
   const int stencil_size = attributes_.stencil ? 8 : 0;
   const int samples = attributes_.antialias ? 4 : 0;
   const int sample_buffers = attributes_.antialias ? 1 : 0;
   const int32 attribs[] = {
     RendererGLContext::ALPHA_SIZE, alpha_size,
     RendererGLContext::DEPTH_SIZE, depth_size,
@@ skipping 1016 matching lines @@
   if (context_lost_callback_) {
     context_lost_callback_->onContextLost();
   }
   RenderViewImpl* renderview =
       web_view_ ? RenderViewImpl::FromWebView(web_view_) : NULL;
   if (renderview)
     renderview->OnViewContextSwapBuffersAborted();
 }
 
 #endif  // defined(ENABLE_GPU)