Move the thread hop for UMA user actions from content:: to base::.

android_webview/browser/aw_metrics_service_client.h

 // Copyright 2015 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 ANDROID_WEBVIEW_BROWSER_AW_METRICS_SERVICE_CLIENT_IMPL_H_
 #define ANDROID_WEBVIEW_BROWSER_AW_METRICS_SERVICE_CLIENT_IMPL_H_
 
 #include <memory>
 #include <string>
 
@@ skipping 48 matching lines @@
   bool GetBrand(std::string* brand_code) override;
   metrics::SystemProfileProto::Channel GetChannel() override;
   std::string GetVersionString() override;
   void OnLogUploadComplete() override;
   void InitializeSystemProfileMetrics(
       const base::Closure& done_callback) override;
   void CollectFinalMetricsForLog(const base::Closure& done_callback) override;
   std::unique_ptr<metrics::MetricsLogUploader> CreateUploader(
       const base::Callback<void(int)>& on_upload_complete) override;
   base::TimeDelta GetStandardUploadInterval() override;
+  scoped_refptr<base::SingleThreadTaskRunner>
+      GetMainThreadTaskRunner() override;
 
  private:
   AwMetricsServiceClient();
   ~AwMetricsServiceClient() override;
 
   void InitializeWithGUID(std::string* guid);
 
   // Callback for metrics::MetricsStateManager::Create
   bool is_reporting_enabled();
 
   bool is_initialized_;
   bool is_enabled_;
   PrefService* pref_service_;
   net::URLRequestContextGetter* request_context_;
   std::unique_ptr<metrics::MetricsStateManager> metrics_state_manager_;
   std::unique_ptr<metrics::MetricsService> metrics_service_;
 
   DISALLOW_COPY_AND_ASSIGN(AwMetricsServiceClient);
 };
 
 }  // namespace android_webview
 
 #endif  // ANDROID_WEBVIEW_BROWSER_AW_METRICS_SERVICE_CLIENT_IMPL_H_