Buffer UI navigation events in DataUseTabModel until rule fetch

chrome/browser/android/data_usage/data_use_tab_model.h

Index: chrome/browser/android/data_usage/data_use_tab_model.h
diff --git a/chrome/browser/android/data_usage/data_use_tab_model.h b/chrome/browser/android/data_usage/data_use_tab_model.h
index 2d71ffac0dde7f3d96058f6f58d090ee694ed49b..bed0ff823525b320b52c748dbae73264430ec186 100644
--- a/chrome/browser/android/data_usage/data_use_tab_model.h
+++ b/chrome/browser/android/data_usage/data_use_tab_model.h
@@ -187,15 +187,41 @@ class DataUseTabModel {
   FRIEND_TEST_ALL_PREFIXES(DataUseTabModelTest,
                            MultipleObserverMultipleStartEndEvents);
   FRIEND_TEST_ALL_PREFIXES(DataUseTabModelTest, ObserverStartEndEvents);
+  FRIEND_TEST_ALL_PREFIXES(DataUseTabModelTest,
+                           ProcessBufferedNavigationEventsAfterRuleFetch);
   FRIEND_TEST_ALL_PREFIXES(DataUseTabModelTest, TabCloseEvent);
   FRIEND_TEST_ALL_PREFIXES(DataUseTabModelTest, TabCloseEventEndsTracking);
   FRIEND_TEST_ALL_PREFIXES(DataUseTabModelTest,
                            UnexpiredTabEntryRemovaltimeHistogram);
   FRIEND_TEST_ALL_PREFIXES(ExternalDataUseObserverTest,
                            MatchingRuleFetchOnControlAppInstall);
+  FRIEND_TEST_ALL_PREFIXES(
+      ExternalDataUseObserverTest,
+      ProcessBufferedNavigationEventsAfterControlAppNotInstalled);
+  FRIEND_TEST_ALL_PREFIXES(ExternalDataUseObserverTest,
+                           ProcessBufferedNavigationEventsAfterRuleFetch);
+  FRIEND_TEST_ALL_PREFIXES(ExternalDataUseObserverTest,
+                           ProcessBufferedNavigationEventsAfterMaxLimit);
 
   typedef base::hash_map<SessionID::id_type, TabDataUseEntry> TabEntryMap;
 
+  // Contains the details of a single UI navigation event.
+  struct DataUseUINavigationEvent {
+    DataUseUINavigationEvent(SessionID::id_type tab_id,
+                             TransitionType transition_type,
+                             GURL url,
+                             std::string package)
+        : tab_id(tab_id),
+          transition_type(transition_type),
+          url(url),
+          package(package) {}
+
+    const SessionID::id_type tab_id;
+    const TransitionType transition_type;
+    const GURL url;
+    const std::string package;
+  };
+
   // Gets the current label of a tab, and the new label if a navigation event
   // occurs in the tab. |tab_id| is the source tab of the generated event,
   // |transition| indicates the type of the UI event/transition,  |url| is the
@@ -231,6 +257,11 @@ class DataUseTabModel {
   // size is |kMaxTabEntries|.
   void CompactTabEntries();
 
+  // Processes the UI navigation events buffered in |data_use_ui_navigations_|
+  // and deletes the vector in |data_use_ui_navigations_| so that navigation
+  // events will not be buffered any more.
+  void ProcessBufferedNavigationEvents();
+
   // Collection of observers that receive tracking session start and end
   // notifications. Notifications are posted on UI thread.
   base::ObserverList<TabDataUseObserver> observers_;
@@ -258,6 +289,15 @@ class DataUseTabModel {
   // True if the external control app is installed.
   bool is_control_app_installed_;
 
+  // Buffer of UI navigation events that occurred until the first rule fetch is
+  // complete or the control app not installed callback was received or until
+  // |kDefaultMaxNavigationEventsBuffered| navigation events were buffered,
+  // whichever occurs first. Existence of the vector in scoped_ptr indicates if
+  // the UI navigation events need to be buffered. If the scoped_ptr contains a
+  // vector all navigation events will be added to it. Otherwise all navigation
+  // events will be processed immediately.
+  scoped_ptr<std::vector<DataUseUINavigationEvent>> data_use_ui_navigations_;
+
   base::ThreadChecker thread_checker_;
 
   base::WeakPtrFactory<DataUseTabModel> weak_factory_;