Make field trials activated in the GPU process be reflected in browser.

chrome/gpu/chrome_content_gpu_client.h

 // 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.
 
 #ifndef CHROME_GPU_CHROME_CONTENT_GPU_CLIENT_H_
 #define CHROME_GPU_CHROME_CONTENT_GPU_CLIENT_H_
 
+#include <memory>
+
 #include "base/macros.h"
+#include "chrome/common/variations/child_process_field_trial_syncer.h"
 #include "content/public/gpu/content_gpu_client.h"
 
 class ChromeContentGpuClient : public content::ContentGpuClient {
  public:
   ChromeContentGpuClient();
   ~ChromeContentGpuClient() override;
 
-  // content::ContentGpuClient implementation.
+  // content::ContentGpuClient:
+  void Initialize(base::FieldTrialList::Observer* observer) override;
   void RegisterMojoServices(content::ServiceRegistry* registry) override;
 
  private:
+  std::unique_ptr<chrome_variations::ChildProcessFieldTrialSyncer>
+      field_trial_syncer_;
+
   DISALLOW_COPY_AND_ASSIGN(ChromeContentGpuClient);
 };
 
 #endif  // CHROME_GPU_CHROME_CONTENT_GPU_CLIENT_H_