Implement UMA log throttling for cellular connections

components/data_use_measurement/content/data_use_measurement.h

 // Copyright 2015 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_DATA_USE_MEASUREMENT_CONTENT_DATA_USE_MEASUREMENT_H_
 #define COMPONENTS_DATA_USE_MEASUREMENT_CONTENT_DATA_USE_MEASUREMENT_H_
 
 #include <stdint.h>
 
 #include <string>
 
+#include "base/callback.h"
 #include "base/macros.h"
 #include "base/memory/scoped_ptr.h"
 #include "build/build_config.h"
 #include "components/data_use_measurement/core/data_use_user_data.h"
+#include "components/metrics/data_use_tracker.h"
 
 #if defined(OS_ANDROID)
 #include "base/android/application_status_listener.h"
 #endif
 
 namespace net {
 class URLRequest;
 }
 
 namespace data_use_measurement {
 
 // Records the data use of user traffic and various services in UMA histograms.
 // The UMA is broken down by network technology used (Wi-Fi vs cellular). On
 // Android, the UMA is further broken down by whether the application was in the
 // background or foreground during the request.
 // TODO(amohammadkhan): Complete the layered architecture.
 // http://crbug.com/527460
 class DataUseMeasurement {
  public:
-  DataUseMeasurement();
+  explicit DataUseMeasurement(
+      const metrics::UpdateUsagePrefCallbackType& metrics_data_use_forwarder);
   ~DataUseMeasurement();
 
   // Records the data use of the |request|, thus |request| must be non-null.
   void ReportDataUseUMA(const net::URLRequest* request) const;
 
 #if defined(OS_ANDROID)
   // This function should just be used for testing purposes. A change in
   // application state can be simulated by calling this function.
   void OnApplicationStateChangeForTesting(
       base::android::ApplicationState application_state);
@@ skipping 10 matching lines @@
   // Returns the current application state (Foreground or Background). It always
   // returns Foreground if Chrome is not running on Android.
   AppState CurrentAppState() const;
 
   // Makes the full name of the histogram. It is made from |prefix| and suffix
   // which is made based on network and application status. suffix is a string
   // representing whether the data use was on the send ("Upstream") or receive
   // ("Downstream") path, whether the app was in the "Foreground" or
   // "Background", and whether a "Cellular" or "WiFi" network was use. For
   // example, "Prefix.Upstream.Foreground.Cellular" is a possible output.
-  std::string GetHistogramName(const char* prefix, TrafficDirection dir) const;
+  std::string GetHistogramName(const char* prefix,
+                               TrafficDirection dir,
+                               bool is_connection_cellular) const;
 
 #if defined(OS_ANDROID)
   // Called whenever the application transitions from foreground to background
   // and vice versa.
   void OnApplicationStateChange(
       base::android::ApplicationState application_state);
 #endif
 
   // A helper function used to record data use of services. It gets the size of
   // exchanged message, its direction (which is upstream or downstream) and
   // reports to two histogram groups. DataUse.MessageSize.ServiceName and
   // DataUse.Services.{Dimensions}. In the second one, services are buckets.
   void ReportDataUsageServices(
       data_use_measurement::DataUseUserData::ServiceName service,
       TrafficDirection dir,
+      bool is_connection_cellular,
       int64_t message_size) const;
 
+  // Callback for updating data use prefs.
+  // TODO(rajendrant): If a similar mechanism would need be used for components
+  // other than metrics, then the better approach would be to refactor this
+  // class to support registering arbitrary observers. crbug.com/601185
+  metrics::UpdateUsagePrefCallbackType metrics_data_use_forwarder_;
+
 #if defined(OS_ANDROID)
   // Application listener store the last known state of the application in this
   // field.
   base::android::ApplicationState app_state_;
 
   // ApplicationStatusListener used to monitor whether the application is in the
   // foreground or in the background. It is owned by DataUseMeasurement.
   scoped_ptr<base::android::ApplicationStatusListener> app_listener_;
 #endif
 
   DISALLOW_COPY_AND_ASSIGN(DataUseMeasurement);
 };
 
 }  // namespace data_use_measurement
 
 #endif  // COMPONENTS_DATA_USE_MEASUREMENT_CONTENT_DATA_USE_MEASUREMENT_H_