Buffer UI navigation events in DataUseTabModel until rule fetch

chrome/browser/android/data_usage/data_use_tab_model.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_DATA_USE_TAB_MODEL_H_
 #define CHROME_BROWSER_ANDROID_DATA_USAGE_DATA_USE_TAB_MODEL_H_
 
 #include <stddef.h>
 
 #include <string>
@@ skipping 175 matching lines @@
                            MatchingRuleClearedOnControlAppUninstall);
   FRIEND_TEST_ALL_PREFIXES(DataUseTabModelTest,
                            MultipleObserverMultipleStartEndEvents);
   FRIEND_TEST_ALL_PREFIXES(DataUseTabModelTest, ObserverStartEndEvents);
   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,
+                           ProcessBufferedNavigationEvents);
 
   typedef base::hash_map<SessionID::id_type, TabDataUseEntry> TabEntryMap;
 
+  // Contains the details of a single UI navigation event.
+  struct DataUseUINavigationEvent {

[tbansal1, 2016/03/29 16:20:41]

Methods should come before fields.

[Raj, 2016/03/29 18:03:21]

Done.

+    SessionID::id_type tab_id;

[tbansal1, 2016/03/29 16:20:41]

can these fields be all const?

[Raj, 2016/03/29 18:03:20]

Done.

+    TransitionType transition_type;
+    GURL url;
+    std::string package;
+    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) {}
+  };
+
   // 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
   // URL in the source tab, |package| indicates the android package name of
   // external application that initiated the event. |current_label|, |new_label|
   // and |is_package_match| should not be null, and are set with current and new
   // labels respectively. |current_label| will be set to empty string, if there
   // is no active tracking session. |new_label| will be set to empty string if
   // there would be no active tracking session if the navigation happens.
   // |is_package_match| will be set to true if a tracking session will start due
@@ skipping 15 matching lines @@
 
   // Ends the current tracking session for tab with id |tab_id|.
   void EndTrackingDataUse(SessionID::id_type tab_id);
 
   // Compacts the tab entry map |active_tabs_| by removing expired tab entries.
   // After removing expired tab entries, if the size of |active_tabs_| exceeds
   // |kMaxTabEntries|, oldest unexpired tab entries will be removed until its
   // size is |kMaxTabEntries|.
   void CompactTabEntries();
 
+  void ProcessBufferedNavigationEvents();

[tbansal1, 2016/03/29 16:20:41]

function comments please.

[Raj, 2016/03/29 18:03:21]

Done.

+
   // Collection of observers that receive tracking session start and end
   // notifications. Notifications are posted on UI thread.
   base::ObserverList<TabDataUseObserver> observers_;
 
   // Maintains the tracking sessions of multiple tabs.
   TabEntryMap active_tabs_;
 
   // Maximum number of tab entries to maintain session information about.
   const size_t max_tab_entries_;
 
   // Maximum number of tracking sessions to maintain per tab.
   const size_t max_sessions_per_tab_;
 
   // Expiration duration for a closed tab entry and an open tab entry
   // respectively.
   const base::TimeDelta closed_tab_expiration_duration_;
   const base::TimeDelta open_tab_expiration_duration_;
 
   // TickClock used for obtaining the current time.
   scoped_ptr<base::TickClock> tick_clock_;
 
   // Stores the matching patterns.
   scoped_ptr<DataUseMatcher> data_use_matcher_;
 
   // True if the external control app is installed.
   bool is_control_app_installed_;
 
+  // Buffers the list of UI navigation events that occurred until the first rule

[tbansal1, 2016/03/29 16:20:41]

s/Buffers the list of/Buffer of/?

[Raj, 2016/03/29 18:03:21]

Done.

+  // 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_;
 
   DISALLOW_COPY_AND_ASSIGN(DataUseTabModel);
 };
 
 }  // namespace android
 
 }  // namespace chrome
 
 #endif  // CHROME_BROWSER_ANDROID_DATA_USAGE_DATA_USE_TAB_MODEL_H_