Add histograms for data usage

chrome/browser/android/data_usage/external_data_use_observer_bridge.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 CHROME_BROWSER_ANDROID_DATA_USAGE_EXTERNAL_DATA_USE_OBSERVER_BRIDGE_H_
 #define CHROME_BROWSER_ANDROID_DATA_USAGE_EXTERNAL_DATA_USE_OBSERVER_BRIDGE_H_
 
 #include <jni.h>
 #include <stdint.h>
 
 #include <string>
 
 #include "base/android/jni_array.h"
 #include "base/android/scoped_java_ref.h"
 #include "base/macros.h"
 #include "base/memory/ref_counted.h"
 #include "base/memory/weak_ptr.h"
 #include "base/threading/thread_checker.h"
 #include "net/base/network_change_notifier.h"
 
 namespace base {
 class SingleThreadTaskRunner;
 class Time;
+class TimeTicks;
 }
 
 namespace chrome {
 
 namespace android {
 
 class DataUseTabModel;
 class ExternalDataUseObserver;
 
 // ExternalDataUseObserverBridge creates and owns a Java listener object
 // that is notified of the data usage observations of Chromium. This class
 // receives regular expressions from the Java listener object. Objects of this
 // class may may be constructed on any thread safe but are immediately moved to
 // the UI thread, and afterwards are accessible only on the UI thread.
 class ExternalDataUseObserverBridge {
  public:
   ExternalDataUseObserverBridge();
   ~ExternalDataUseObserverBridge();
 
   // Initializes |this| on UI thread by constructing the
   // |j_external_data_use_observer_|, and fetches matching rules from
   // |j_external_data_use_observer_|.
   void Init(scoped_refptr<base::SingleThreadTaskRunner> io_task_runner,
             base::WeakPtr<ExternalDataUseObserver> external_data_use_observer,
             DataUseTabModel* data_use_tab_model);
 
   // Fetches matching rules from Java. Returns result asynchronously via
   // FetchMatchingRulesDone. FetchMatchingRules should not be called if a
   // fetch to matching rules is already in progress.
-  void FetchMatchingRules() const;
+  void FetchMatchingRules();
 
   // Called by Java when new matching rules have been fetched.
   // |app_package_name| is the package name of the app that should be matched.
   // |domain_path_regex| is the regex to be used for matching URLs. |label| is
   // the label that must be applied to data reports corresponding to the
   // matching rule, and must uniquely identify the matching rule. Each element
   // in |label| must have non-zero length. The three vectors should have equal
   // length. The vectors may be empty which implies that no matching rules are
   // active.
   void FetchMatchingRulesDone(
@@ skipping 30 matching lines @@
   // reports are submitted to |j_external_data_use_observer_|.
   base::android::ScopedJavaGlobalRef<jobject> j_external_data_use_observer_;
 
   // |external_data_use_observer_| owns |this|. |external_data_use_observer_| is
   // notified of results from Java code by |this|.
   base::WeakPtr<ExternalDataUseObserver> external_data_use_observer_;
 
   // |data_use_tab_model_| is notified of the matching rules on UI thread.
   base::WeakPtr<DataUseTabModel> data_use_tab_model_;
 
+  // The time of request when the matching rules are fetched for the first time.
+  base::TimeTicks matching_rules_first_fetch_time_;
+
   // |io_task_runner_| accesses ExternalDataUseObserver members on IO thread.
   scoped_refptr<base::SingleThreadTaskRunner> io_task_runner_;
 
   base::ThreadChecker thread_checker_;
 
   DISALLOW_COPY_AND_ASSIGN(ExternalDataUseObserverBridge);
 };
 
 bool RegisterExternalDataUseObserver(JNIEnv* env);
 
 }  // namespace android
 
 }  // namespace chrome
 
 #endif  // CHROME_BROWSER_ANDROID_DATA_USAGE_EXTERNAL_DATA_USE_OBSERVER_BRIDGE_H_