Add nullptr check for GpuProcessHost when allocating GpuMemoryBuffer

content/browser/gpu/browser_gpu_memory_buffer_manager.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 "content/browser/gpu/browser_gpu_memory_buffer_manager.h"
 
 #include <utility>
 
 #include "base/bind.h"
 #include "base/command_line.h"
@@ skipping 320 matching lines @@
     gfx::GpuMemoryBufferId id,
     const gfx::Size& size,
     gfx::BufferFormat format,
     gfx::BufferUsage usage,
     gpu::SurfaceHandle surface_handle,
     int client_id,
     const CreateCallback& callback) {
   DCHECK_CURRENTLY_ON(BrowserThread::IO);
   BufferMap& buffers = clients_[client_id];
 
+  GpuProcessHost* host = GpuProcessHost::Get();
+  if (!host) {
+    DLOG(ERROR) << "Cannot allocate GpuMemoryBuffer with no GpuProcessHost.";
+    callback.Run(gfx::GpuMemoryBufferHandle());
+    return;
+  }
+
   // Note: Handling of cases where the client is removed before the allocation
   // completes is less subtle if we set the buffer type to EMPTY_BUFFER here
   // and verify that this has not changed when creation completes.
   auto insert_result = buffers.insert(std::make_pair(
       id, BufferInfo(size, gfx::EMPTY_BUFFER, format, usage, 0)));
   if (!insert_result.second) {
     DLOG(ERROR) << "Child process attempted to create a GpuMemoryBuffer with "
                    "an existing ID.";
     callback.Run(gfx::GpuMemoryBufferHandle());
     return;
   }
 
-  GpuProcessHost* host = GpuProcessHost::Get();
   // Note: Unretained is safe as IO thread is stopped before manager is
   // destroyed.
   host->CreateGpuMemoryBuffer(
       id, size, format, usage, client_id, surface_handle,
       base::Bind(&BrowserGpuMemoryBufferManager::GpuMemoryBufferCreatedOnIO,
                  base::Unretained(this), id, surface_handle, client_id,
                  host->host_id(), callback));
 }
 
 void BrowserGpuMemoryBufferManager::GpuMemoryBufferCreatedOnIO(
@@ skipping 113 matching lines @@
       format(format),
       usage(usage),
       gpu_host_id(gpu_host_id) {}
 
 BrowserGpuMemoryBufferManager::BufferInfo::BufferInfo(const BufferInfo& other) =
     default;
 
 BrowserGpuMemoryBufferManager::BufferInfo::~BufferInfo() {}
 
 }  // namespace content