Revert 128016 - Make sandbox explicitly block opening broker and sandboxed processes

content/common/gpu/gpu_channel.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.
 
 #if defined(OS_WIN)
 #include <windows.h>
 #endif
 
 #include "content/common/gpu/gpu_channel.h"
 
@@ skipping 297 matching lines @@
   router_.RemoveRoute(route_id);
 }
 
 bool GpuChannel::ShouldPreferDiscreteGpu() const {
   return num_contexts_preferring_discrete_gpu_ > 0;
 }
 
 void GpuChannel::OnInitialize(base::ProcessHandle renderer_process) {
   // Initialize should only happen once.
   DCHECK(!renderer_process_);
-  renderer_process_ = renderer_process;
+
+  // Verify that the renderer has passed its own process handle.
+  if (base::GetProcId(renderer_process) == renderer_pid_)
+    renderer_process_ = renderer_process;
 }
 
 void GpuChannel::OnCreateOffscreenCommandBuffer(
     const gfx::Size& size,
     const GPUCreateCommandBufferConfig& init_params,
     IPC::Message* reply_message) {
   int32 route_id = MSG_ROUTING_NONE;
 
   content::GetContentClient()->SetActiveURL(init_params.active_url);
 #if defined(ENABLE_GPU)
@@ skipping 112 matching lines @@
 
 #if defined(OS_POSIX)
 int GpuChannel::TakeRendererFileDescriptor() {
   if (!channel_.get()) {
     NOTREACHED();
     return -1;
   }
   return channel_->TakeClientFileDescriptor();
 }
 #endif  // defined(OS_POSIX)