Move EntropyProvider Source From MetricsService to MetricsServicesManager

components/metrics_services_manager/metrics_services_manager.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 COMPONENTS_METRICS_SERVICES_MANAGER_METRICS_SERVICES_MANAGER_H_
 #define COMPONENTS_METRICS_SERVICES_MANAGER_METRICS_SERVICES_MANAGER_H_
 
 #include <memory>
 
 #include "base/macros.h"
+#include "base/metrics/field_trial.h"
 #include "base/threading/thread_checker.h"
 
 namespace base {
 class FilePath;
 }
 
 namespace metrics {
 class MetricsService;
 class MetricsServiceClient;
 class MetricsStateManager;
@@ skipping 14 matching lines @@
 // MetricsServicesManager is a helper class for embedders that use the various
 // metrics-related services in a Chrome-like fashion: MetricsService (via its
 // client), RapporService and VariationsService.
 class MetricsServicesManager {
  public:
   // Creates the MetricsServicesManager with the given client.
   explicit MetricsServicesManager(
       std::unique_ptr<MetricsServicesManagerClient> client);
   virtual ~MetricsServicesManager();
 
+  // Returns the preferred entropy provider used to seed persistent activities
+  // based on whether or not metrics reporting is permitted on this client.
+  //
+  // If there's consent to report metrics, this method returns an entropy
+  // provider that has a high source of entropy, partially based on the client
+  // ID. Otherwise, it returns an entropy provider that is based on a low
+  // entropy source.
+  std::unique_ptr<const base::FieldTrial::EntropyProvider>
+  CreateEntropyProvider();

[brettw, 2016/09/14 22:22:03]

Indent 4 spaces as above.

[sdefresne, 2016/09/15 11:30:07]

I think this is correctly indented (at least this is how clang-format indents
methods).

[robliao, 2016/09/15 14:31:18]

The stated rule:
If you break after the return type of a function declaration or definition, do
not indent.
https://google.github.io/styleguide/cppguide.html#Function_Declarations_and_D...

Personally, I would prefer the 4 space indent here.

+
   // Returns the MetricsService, creating it if it hasn't been created yet (and
   // additionally creating the MetricsServiceClient in that case).
   metrics::MetricsService* GetMetricsService();
 
   // Returns the RapporService, creating it if it hasn't been created yet.
   rappor::RapporService* GetRapporService();
 
   // Returns the VariationsService, creating it if it hasn't been created yet.
   variations::VariationsService* GetVariationsService();
 
@@ skipping 45 matching lines @@
 
   // The VariationsService, for server-side experiments infrastructure.
   std::unique_ptr<variations::VariationsService> variations_service_;
 
   DISALLOW_COPY_AND_ASSIGN(MetricsServicesManager);
 };
 
 }  // namespace metrics_services_manager
 
 #endif  // COMPONENTS_METRICS_SERVICES_MANAGER_METRICS_SERVICES_MANAGER_H_