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