Pass MetricsServiceClient into MetricsService, and create a simple stubbed TestMetricsServiceClient…

chrome/browser/metrics/metrics_service.h

 // Copyright (c) 2012 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.
 
 // This file defines a service that collects information about the user
 // experience in order to help improve future versions of the app.
 
 #ifndef CHROME_BROWSER_METRICS_METRICS_SERVICE_H_
 #define CHROME_BROWSER_METRICS_METRICS_SERVICE_H_
 
@@ skipping 55 matching lines @@
 struct WebPluginInfo;
 }
 
 namespace extensions {
 class ExtensionDownloader;
 class ManifestFetchData;
 class MetricsPrivateGetIsCrashReportingEnabledFunction;
 }
 
 namespace metrics {
+class MetricsServiceClient;
 class MetricsStateManager;
 }
 
 namespace net {
 class URLFetcher;
 }
 
 namespace prerender {
 bool IsOmniboxEnabled(Profile* profile);
 }
@@ skipping 38 matching lines @@
     UNINITIALIZED_PHASE = 0,
     START_METRICS_RECORDING = 100,
     CREATE_PROFILE = 200,
     STARTUP_TIMEBOMB_ARM = 300,
     THREAD_WATCHER_START = 400,
     MAIN_MESSAGE_LOOP_RUN = 500,
     SHUTDOWN_TIMEBOMB_ARM = 600,
     SHUTDOWN_COMPLETE = 700,
   };
 
-  // Creates the MetricsService with the given |state_manager|. Does not take
-  // ownership of |state_manager|, instead stores a weak pointer to it. Caller
-  // should ensure that |state_manager| is valid for the lifetime of this class.
-  explicit MetricsService(metrics::MetricsStateManager* state_manager);
+  // Creates the MetricsService with the given |state_manager| and |client|.
+  // Does not take ownership of |state_manager| or |client|; instead stores a
+  // weak pointer to each. Caller should ensure that |state_manager| and
+  // |client| are valid for the lifetime of this class.
+  MetricsService(metrics::MetricsStateManager* state_manager,
+                 metrics::MetricsServiceClient* client);
   virtual ~MetricsService();
 
   // Initializes metrics recording state. Updates various bookkeeping values in
   // prefs and sets up the scheduler. This is a separate function rather than
   // being done by the constructor so that field trials could be created before
   // this is run.
   void InitializeMetricsRecordingState();
 
   // Starts the metrics system, turning on recording and uploading of metrics.
   // Should be called when starting up with metrics enabled, or when metrics
@@ skipping 330 matching lines @@
   // process, and false otherwise.
   static bool IsPluginProcess(int process_type);
 
   // Returns a list of synthetic field trials that were active for the entire
   // duration of the current log.
   void GetCurrentSyntheticFieldTrials(
       std::vector<chrome_variations::ActiveGroupId>* synthetic_trials);
 
   // Used to manage various metrics reporting state prefs, such as client id,
   // low entropy source and whether metrics reporting is enabled. Weak pointer.
-  metrics::MetricsStateManager* state_manager_;
+  metrics::MetricsStateManager* const state_manager_;
+
+  // Used to interact with the embedder. Weak pointer; must outlive |this|
+  // instance.
+  metrics::MetricsServiceClient* const client_;
 
   base::ActionCallback action_callback_;
 
   content::NotificationRegistrar registrar_;
 
   // Set to true when |ResetMetricsIDsIfNecessary| is called for the first time.
   // This prevents multiple resets within the same Chrome session.
   bool metrics_ids_reset_check_performed_;
 
   // Indicate whether recording and reporting are currently happening.
@@ skipping 141 matching lines @@
 
   // Registers/unregisters |observer| to receive MetricsLog notifications
   // from metrics service.
   static void AddMetricsServiceObserver(MetricsServiceObserver* observer);
   static void RemoveMetricsServiceObserver(MetricsServiceObserver* observer);
 
   DISALLOW_IMPLICIT_CONSTRUCTORS(MetricsServiceHelper);
 };
 
 #endif  // CHROME_BROWSER_METRICS_METRICS_SERVICE_H_