// 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 ASH_METRICS_TASK_SWITCH_METRICS_RECORDER_H_ #define ASH_METRICS_TASK_SWITCH_METRICS_RECORDER_H_ #include #include #include #include "ash/ash_export.h" #include "ash/metrics/task_switch_source.h" namespace ash { class TaskSwitchTimeTracker; // The TaskSwitchMetricsRecorder class records UMA metrics related to task // switching. The main purpose of the TaskSwitchMetricsRecorder is to track time // deltas between task switches and record histograms of the deltas. class ASH_EXPORT TaskSwitchMetricsRecorder { public: TaskSwitchMetricsRecorder(); TaskSwitchMetricsRecorder(const TaskSwitchMetricsRecorder&) = delete; TaskSwitchMetricsRecorder& operator=(const TaskSwitchMetricsRecorder&) = delete; virtual ~TaskSwitchMetricsRecorder(); // Notifies |this| that a "navigate to" task switch has occurred from the // specified |task_switch_source|. The metrics associated with // TaskSwitchSource::ANY source will be updated as well. // // NOTE: A |task_switch_source| value of TaskSwitchSource::ANY should not be // used and behavior is undefined if it is. // // A "navigate to" operation is defined by a task switch where the specific // task that becomes active is user-predictable (e.g., Alt+Tab accelerator, // launching a new window via the shelf, etc). Contrast to a "navigate away" // operation which is defined as a user interaction that navigates away from a // specified task and the next task that becomes active is likely not // user-predictable (e.g., closing or minimizing a window, closing a tab, // etc). // // Will add an entry to |histogram_map_| when called for the first time for // each |task_switch_source| value. void OnTaskSwitch(TaskSwitchSource task_switch_source); private: // Internal implementation of OnTaskSwitch(TaskSwitchSource) that will accept // the TaskSwitchSource::ANY value. void OnTaskSwitchInternal(TaskSwitchSource task_switch_source); // Returns the TaskSwitchTimeTracker associated with the specified // |task_switch_source|. May return nullptr if mapping does not exist yet. TaskSwitchTimeTracker* FindTaskSwitchTimeTracker( TaskSwitchSource task_switch_source); // Adds a TaskSwitchTimeTracker to |histogram_map_| for the specified // |task_switch_source|. Behavior is undefined if a TaskSwitchTimeTracker // |histogram_map_| already has an entry for |task_switch_source|. void AddTaskSwitchTimeTracker(TaskSwitchSource task_switch_source); // Tracks TaskSwitchSource to TaskSwitchTimeTracker mappings. The // |histogram_map_| is populated on demand the first time a // TaskSwitchTimeTracker is needed for a given source. std::unordered_map> histogram_map_; }; } // namespace ash #endif // ASH_METRICS_TASK_SWITCH_METRICS_RECORDER_H_