MD Settings: implement metrics reporting checkbox on desktop

chrome/browser/metrics/chrome_metrics_service_accessor.h

 // 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.
 
 #ifndef CHROME_BROWSER_METRICS_CHROME_METRICS_SERVICE_ACCESSOR_H_
 #define CHROME_BROWSER_METRICS_CHROME_METRICS_SERVICE_ACCESSOR_H_
 
 #include <stdint.h>
 #include <string>
 #include <vector>
@@ skipping 44 matching lines @@
 
 namespace safe_browsing {
 class DownloadSBClient;
 class IncidentReportingService;
 class SafeBrowsingService;
 class SafeBrowsingUIManager;
 class SRTFetcher;
 class SRTGlobalError;
 }
 
+namespace settings {
+class MetricsReportingHandler;
+}
+
 namespace speech {
 class ChromeSpeechRecognitionManagerDelegate;
 }
 
 namespace system_logs {
 class ChromeInternalLogSource;
 }
 
 // This class limits and documents access to metrics service helper methods.
 // Since these methods are private, each user has to be explicitly declared
@@ skipping 12 matching lines @@
   friend class domain_reliability::DomainReliabilityServiceFactory;
   friend class extensions::ChromeExtensionWebContentsObserver;
   friend class extensions::FileManagerPrivateIsUMAEnabledFunction;
   friend class extensions::MetricsPrivateGetIsCrashReportingEnabledFunction;
   friend void ChangeMetricsReportingStateWithReply(
       bool,
       const OnMetricsReportingCallbackType&);
   friend class options::BrowserOptionsHandler;
   friend bool prerender::IsOmniboxEnabled(Profile* profile);
   friend class safe_browsing::IncidentReportingService;
+  friend class settings::MetricsReportingHandler;
   friend class speech::ChromeSpeechRecognitionManagerDelegate;
   friend class StackSamplingConfiguration;
   friend class system_logs::ChromeInternalLogSource;
   friend class UmaSessionStats;
   friend class safe_browsing::SRTFetcher;
   friend class safe_browsing::SRTGlobalError;
   friend class safe_browsing::DownloadSBClient;
   friend class safe_browsing::SafeBrowsingService;
   friend class safe_browsing::SafeBrowsingUIManager;
   friend void SyzyASANRegisterExperiment(const char*, const char*);
@@ skipping 25 matching lines @@
   // with g_browser_process->metrics_service(). See that function's declaration
   // for details.
   static bool RegisterSyntheticFieldTrialWithNameHash(
       uint32_t trial_name_hash,
       const std::string& group_name);
 
   DISALLOW_IMPLICIT_CONSTRUCTORS(ChromeMetricsServiceAccessor);
 };
 
 #endif  // CHROME_BROWSER_METRICS_CHROME_METRICS_SERVICE_ACCESSOR_H_