Simulate variation seeds using installed version string.

chrome/browser/metrics/variations/variations_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.
 
 #ifndef CHROME_BROWSER_METRICS_VARIATIONS_VARIATIONS_SERVICE_H_
 #define CHROME_BROWSER_METRICS_VARIATIONS_VARIATIONS_SERVICE_H_
 
 #include <string>
 
 #include "base/compiler_specific.h"
 #include "base/gtest_prod_util.h"
 #include "base/memory/scoped_ptr.h"
+#include "base/memory/weak_ptr.h"
 #include "base/metrics/field_trial.h"
 #include "base/time/time.h"
+#include "base/version.h"

[Ilya Sherman, 2014/06/17 21:24:59]

nit: Can this be forward-declared?

[Alexei Svitkine (slow), 2014/06/17 22:15:54]

Done.

 #include "chrome/browser/metrics/variations/variations_request_scheduler.h"
 #include "chrome/browser/metrics/variations/variations_seed_store.h"
 #include "chrome/browser/web_resource/resource_request_allowed_notifier.h"
 #include "chrome/common/chrome_version_info.h"
 #include "net/url_request/url_fetcher_delegate.h"
 #include "url/gurl.h"
 
 #if defined(OS_WIN)
 #include "chrome/browser/metrics/variations/variations_registry_syncer_win.h"
 #endif
@@ skipping 113 matching lines @@
   // Checks if prerequisites for fetching the Variations seed are met, and if
   // so, performs the actual fetch using |DoActualFetch|.
   void FetchVariationsSeed();
 
   // net::URLFetcherDelegate implementation:
   virtual void OnURLFetchComplete(const net::URLFetcher* source) OVERRIDE;
 
   // ResourceRequestAllowedNotifier::Observer implementation:
   virtual void OnResourceRequestsAllowed() OVERRIDE;
 
+  // Performs a variations seed simulation with the given |seed| and |version|.

[Ilya Sherman, 2014/06/17 21:24:59]

From just reading the declaration and comment, it's unclear to me why this is a
void method.  What happens to the result of the simulation?

[Alexei Svitkine (slow), 2014/06/17 22:15:54]

Currently, it only logs histograms. In another CL (that's under review) it will
notify observers based on the simulation results. I've expanded the comment to
mention the current behavior.

+  void PerformSimulationWithVersion(scoped_ptr<VariationsSeed> seed,
+                                    const base::Version& version);
+
   // Record the time of the most recent successful fetch.
   void RecordLastFetchTime();
 
   // The pref service used to store persist the variations seed.
   PrefService* local_state_;
 
   // Used for instantiating entropy providers for variations seed simulation.
   // Weak pointer.
   metrics::MetricsStateManager* state_manager_;
 
@@ skipping 28 matching lines @@
 
   // The start time of the last seed request. This is used to measure the
   // latency of seed requests. Initially zero.
   base::TimeTicks last_request_started_time_;
 
 #if defined(OS_WIN)
   // Helper that handles synchronizing Variations with the Registry.
   VariationsRegistrySyncer registry_syncer_;
 #endif
 
+  base::WeakPtrFactory<VariationsService> weak_ptr_factory_;
+
   DISALLOW_COPY_AND_ASSIGN(VariationsService);
 };
 
 }  // namespace chrome_variations
 
 #endif  // CHROME_BROWSER_METRICS_VARIATIONS_VARIATIONS_SERVICE_H_