Add histograms for data usage

chrome/browser/android/data_usage/external_data_use_observer_bridge.h

Index: chrome/browser/android/data_usage/external_data_use_observer_bridge.h
diff --git a/chrome/browser/android/data_usage/external_data_use_observer_bridge.h b/chrome/browser/android/data_usage/external_data_use_observer_bridge.h
index 2727c4074901f4ee9a56f3fd69406092ca6f2bda..4925870aa6093b2c00b6ca49060fcf85c2aad8e5 100644
--- a/chrome/browser/android/data_usage/external_data_use_observer_bridge.h
+++ b/chrome/browser/android/data_usage/external_data_use_observer_bridge.h
@@ -21,6 +21,7 @@
 namespace base {
 class SingleThreadTaskRunner;
 class Time;
+class TimeTicks;
 }
 
 namespace chrome {
@@ -101,6 +102,12 @@ class ExternalDataUseObserverBridge {
   // |data_use_tab_model_| is notified of the matching rules on UI thread.
   base::WeakPtr<DataUseTabModel> data_use_tab_model_;
 
+  // The construction time of |this|.
+  const base::TimeTicks construct_time_;
+
+  // True if matching rules are fetched for the first time.
+  bool is_first_matching_rule_fetch_;
+
   // |io_task_runner_| accesses ExternalDataUseObserver members on IO thread.
   scoped_refptr<base::SingleThreadTaskRunner> io_task_runner_;