mus-gpu: Allow connection request to gpu to fail.

services/ui/public/cpp/gpu/gpu_service.cc

 // Copyright 2016 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 "services/ui/public/cpp/gpu/gpu_service.h"
 
 #include "base/command_line.h"
 #include "base/memory/singleton.h"
 #include "base/threading/thread_task_runner_handle.h"
 #include "build/build_config.h"
@@ skipping 95 matching lines @@
 }
 
 void GpuService::OnEstablishedGpuChannel(
     int client_id,
     mojo::ScopedMessagePipeHandle channel_handle,
     const gpu::GPUInfo& gpu_info) {
   DCHECK(IsMainThread());
   DCHECK(gpu_service_.get());
   DCHECK(!gpu_channel_);
 
-  if (client_id) {
+  if (client_id && channel_handle.is_valid()) {
     gpu_channel_ = gpu::GpuChannelHost::Create(
         this, client_id, gpu_info, IPC::ChannelHandle(channel_handle.release()),
         &shutdown_event_, gpu_memory_buffer_manager_.get());
   }
 
   gpu_service_.reset();
   for (const auto& i : establish_callbacks_)
     i.Run(gpu_channel_);
   establish_callbacks_.clear();
 }
@@ skipping 20 matching lines @@
   MojoResult result = mojo::UnwrapSharedMemoryHandle(
       std::move(handle), &platform_handle, &shared_memory_size, &readonly);
   if (result != MOJO_RESULT_OK)
     return nullptr;
   DCHECK_EQ(shared_memory_size, size);
 
   return base::MakeUnique<base::SharedMemory>(platform_handle, readonly);
 }
 
 }  // namespace ui