ash/metrics/task_switch_metrics_recorder.h

   1 // Copyright 2015 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #ifndef ASH_METRICS_TASK_SWITCH_METRIC_RECORDER_H_
   6 #define ASH_METRICS_TASK_SWITCH_METRIC_RECORDER_H_
   7
   8 #include <string>
   9
  10 #include "ash/ash_export.h"
  11 #include "base/containers/scoped_ptr_hash_map.h"
  12
  13 namespace ash {
  14
  15 class TaskSwitchTimeTracker;
  16
  17 // The TaskSwitchMetricsRecorder class records UMA metrics related to task
  18 // switching. The main purpose of the TaskSwitchMetricsRecorder is to track time
  19 // deltas between task switches and record histograms of the deltas.
  20 class ASH_EXPORT TaskSwitchMetricsRecorder {
  21  public:
  22   // Enumeration of the different user interfaces that could be the source of
  23   // a task switch. Note this is not necessarily comprehensive of all sources.
  24   enum TaskSwitchSource {
  25     // Task switches from selecting items in the app list.
  26     kAppList,
  27     // Task switches caused by selecting a window from overview mode which is
  28     // different from the previously-active window.
  29     kOverviewMode,
  30     // All task switches caused by shelf buttons, not including sub-menus.
  31     kShelf,
  32     // All task switches caused by the tab strip.
  33     kTabStrip,
  34     // Task switches caused by the WindowCycleController (ie Alt+Tab).
  35     kWindowCycleController
  36   };
  37
  38   TaskSwitchMetricsRecorder();
  39   virtual ~TaskSwitchMetricsRecorder();
  40
  41   // Notifies |this| that a "navigate to" task switch has occurred. A
  42   // "navigate to" operation is defined by a task switch where the specific task
  43   // that becomes active is user-predictable (ie Alt+Tab accelerator, launching
  44   // a new window via the shelf, etc). Contrast to a "navigate away" operation
  45   // which is defined as a user interaction that navigates away from a specified
  46   // task and the next task that becomes active is likely not user-predictable
  47   // (ie. closing or minimizing a window, closing a tab, etc).
  48   //
  49   // Will add an entry to |histogram_map_| when called for the first time for
  50   // each |task_switch_source| value.
  51   void OnTaskSwitch(TaskSwitchSource task_switch_source);
  52
  53  private:
  54   // Returns the TaskSwitchTimeTracker associated with the specified
  55   // |task_switch_source|. May return nullptr if mapping does not exist yet.
  56   TaskSwitchTimeTracker* FindTaskSwitchTimeTracker(
  57       TaskSwitchSource task_switch_source);
  58
  59   // Adds a TaskSwitchTimeTracker to |histogram_map_| for the specified
  60   // |task_switch_source|. Behavior is undefined if a TaskSwitchTimeTracker
  61   // |histogram_map_| already has an entry for |task_switch_source|.
  62   void AddTaskSwitchTimeTracker(TaskSwitchSource task_switch_source);
  63
  64   // Tracks TaskSwitchSource to TaskSwitchTimeTracker mappings. The
  65   // |histogram_map_| is populated on demand the first time a
  66   // TaskSwitchTimeTracker is needed for a given source.
  67   base::ScopedPtrHashMap<int, scoped_ptr<TaskSwitchTimeTracker>> histogram_map_;
  68
  69   DISALLOW_COPY_AND_ASSIGN(TaskSwitchMetricsRecorder);
  70 };
  71
  72 }  // namespace ash
  73
  74 #endif  // ASH_METRICS_TASK_SWITCH_METRIC_RECORDER_H_