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 aura {
  14 class Window;
  15 }  // namespace aura
  16
  17 namespace ash {
  18
  19 class TaskSwitchTimeTracker;
  20
  21 // The TaskSwitchMetricsRecorder class records UMA metrics related to task
  22 // switching. The main purpose of the TaskSwitchMetricsRecorder is to track time
  23 // deltas between task switches and record histograms of the deltas.
  24 class ASH_EXPORT TaskSwitchMetricsRecorder {
  25  public:
  26   // Enumeration of the different user interfaces that could be the source of
  27   // a task switch. Note this is not necessarily comprehensive of all sources.
  28   enum TaskSwitchSource {
  29     // Task switches caused by any two sources in this enum. NOTE: This value
  30     // should NOT be used outside of this class.
  31     ANY,
  32     // Task switches from selecting items in the app list.
  33     APP_LIST,
  34     // Task switches caused by the user activating a task window by clicking or
  35     // tapping on it.
  36     DESKTOP,
  37     // Task switches caused by selecting a window from overview mode which is
  38     // different from the previously-active window.
  39     OVERVIEW_MODE,
  40     // All task switches caused by shelf buttons, not including sub-menus.
  41     SHELF,
  42     // All task switches caused by the tab strip.
  43     TAB_STRIP,
  44     // Task switches caused by the WindowCycleController (ie Alt+Tab).
  45     WINDOW_CYCLE_CONTROLLER
  46   };
  47
  48   TaskSwitchMetricsRecorder();
  49   virtual ~TaskSwitchMetricsRecorder();
  50
  51   // Notifies |this| that a "navigate to" task switch has occurred from the
  52   // specified |task_switch_source|. The metrics associated with
  53   // TaskSwitchSource::ANY source will be updated as well.
  54   //
  55   // NOTE: A |task_switch_source| value of TaskSwitchSource::ANY should not be
  56   // used and behavior is undefined if it is.
  57   //
  58   // A "navigate to" operation is defined by a task switch where the specific
  59   // task that becomes active is user-predictable (e.g., Alt+Tab accelerator,
  60   // launching a new window via the shelf, etc). Contrast to a "navigate away"
  61   // operation which is defined as a user interaction that navigates away from a
  62   // specified task and the next task that becomes active is likely not
  63   // user-predictable (e.g., closing or minimizing a window, closing a tab,
  64   // etc).
  65   //
  66   // Will add an entry to |histogram_map_| when called for the first time for
  67   // each |task_switch_source| value.
  68   void OnTaskSwitch(TaskSwitchSource task_switch_source);
  69
  70  private:
  71   // Internal implementation of OnTaskSwitch(TaskSwitchSource) that will accept
  72   // the TaskSwitchSource::ANY value.
  73   void OnTaskSwitchInternal(TaskSwitchSource task_switch_source);
  74
  75   // Returns the TaskSwitchTimeTracker associated with the specified
  76   // |task_switch_source|. May return nullptr if mapping does not exist yet.
  77   TaskSwitchTimeTracker* FindTaskSwitchTimeTracker(
  78       TaskSwitchSource task_switch_source);
  79
  80   // Adds a TaskSwitchTimeTracker to |histogram_map_| for the specified
  81   // |task_switch_source|. Behavior is undefined if a TaskSwitchTimeTracker
  82   // |histogram_map_| already has an entry for |task_switch_source|.
  83   void AddTaskSwitchTimeTracker(TaskSwitchSource task_switch_source);
  84
  85   // Tracks TaskSwitchSource to TaskSwitchTimeTracker mappings. The
  86   // |histogram_map_| is populated on demand the first time a
  87   // TaskSwitchTimeTracker is needed for a given source.
  88   base::ScopedPtrHashMap<int, scoped_ptr<TaskSwitchTimeTracker>> histogram_map_;
  89
  90   DISALLOW_COPY_AND_ASSIGN(TaskSwitchMetricsRecorder);
  91 };
  92
  93 }  // namespace ash
  94
  95 #endif  // ASH_METRICS_TASK_SWITCH_METRIC_RECORDER_H_