MD Settings: implement metrics reporting checkbox on desktop

chrome/browser/ui/webui/settings/metrics_reporting_handler.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_BROWSER_UI_WEBUI_SETTINGS_METRICS_REPORTING_HANDLER_H_
+#define CHROME_BROWSER_UI_WEBUI_SETTINGS_METRICS_REPORTING_HANDLER_H_
+
+#if !defined(GOOGLE_CHROME_BUILD) || defined(OS_CHROMEOS)
+#error This handler should only be included on Google Chrome for Mac/Win/Linux
+#endif
+
+#include <memory>
+
+#include "base/macros.h"
+#include "chrome/browser/ui/webui/settings/settings_page_ui_handler.h"
+#include "components/policy/core/common/policy_service.h"
+#include "components/prefs/pref_member.h"
+
+namespace base {
+class DictionaryValue;
+}
+
+namespace settings {
+
+class MetricsReportingHandler : public SettingsPageUIHandler {
+ public:
+  MetricsReportingHandler();
+  ~MetricsReportingHandler() override;
+
+  // SettingsPageUIHandler:
+  void RegisterMessages() override;
+  void OnJavascriptAllowed() override;
+  void OnJavascriptDisallowed() override;
+
+ protected:
+  // Handler for "getMetricsReporting" message. No arguments. Protected for
+  // testing.
+  void HandleGetMetricsReporting(const base::ListValue* args);
+
+ private:
+  // Describes the state of metrics reporting in a base::DictionaryValue.
+  // Friends with ChromeMetricsServiceAccessor.
+  std::unique_ptr<base::DictionaryValue> CreateMetricsReportingDict();
+
+  // Handler for "setMetricsReportingEnabled" message. Passed a single,
+  // |enabled| boolean argument.
+  void HandleSetMetricsReportingEnabled(const base::ListValue* args);
+
+  // Called when the policies that affect whether metrics reporting is managed
+  // change.
+  void OnPolicyChanged(const base::Value* current_policy,
+                       const base::Value* previous_policy);
+
+  // Called when the local state pref controlling metrics reporting changes.
+  void OnPrefChanged(const std::string& pref_name);
+
+  // Sends a "metrics-reporting-change" WebUI listener event to the page.
+  void SendMetricsReportingChange();
+
+  // Used to track pref changes that affect whether metrics reporting is
+  // enabled.
+  std::unique_ptr<BooleanPrefMember> pref_member_;
+
+  // Used to track policy changes that affect whether metrics reporting is
+  // enabled or managed.
+  std::unique_ptr<policy::PolicyChangeRegistrar> policy_registrar_;
+
+  DISALLOW_COPY_AND_ASSIGN(MetricsReportingHandler);
+};
+
+}  // namespace settings
+
+#endif  // CHROME_BROWSER_UI_WEBUI_SETTINGS_METRICS_REPORTING_HANDLER_H_