Added Ash.TimeBetweenTaskSwitches to record time deltas between all recorded task switches.

TEST=TaskSwitchMetricsRecorderTest.VerifyTaskSwitchesRecordInAllTaskSwitchHistogram

BUG=487745

Review URL: https://codereview.chromium.org/1148723006

Cr-Commit-Position: refs/heads/master@{#333658}

ash/metrics/task_switch_metrics_recorder.cc

@@ -10,6 +10,8 @@ namespace ash {
 
 namespace {
 
+const char kAshTaskSwitchHistogramName[] = "Ash.TimeBetweenTaskSwitches";
+
 const char kDesktopHistogramName[] =
     "Ash.Desktop.TimeBetweenNavigateToTaskSwitches";
 
@@ -31,6 +33,8 @@ const char kOverviewModeHistogramName[] =
 const char* GetHistogramName(
     TaskSwitchMetricsRecorder::TaskSwitchSource task_switch_source) {
   switch (task_switch_source) {
+    case TaskSwitchMetricsRecorder::kAny:
+      return kAshTaskSwitchHistogramName;
     case TaskSwitchMetricsRecorder::kAppList:
       return kAppListHistogramName;
     case TaskSwitchMetricsRecorder::kDesktop:
@@ -58,6 +62,15 @@ TaskSwitchMetricsRecorder::~TaskSwitchMetricsRecorder() {
 
 void TaskSwitchMetricsRecorder::OnTaskSwitch(
     TaskSwitchSource task_switch_source) {
+  DCHECK_NE(task_switch_source, kAny);
+  if (task_switch_source != kAny) {
+    OnTaskSwitchInternal(task_switch_source);
+    OnTaskSwitchInternal(kAny);
+  }
+}
+
+void TaskSwitchMetricsRecorder::OnTaskSwitchInternal(
+    TaskSwitchSource task_switch_source) {
   TaskSwitchTimeTracker* task_switch_time_tracker =
       FindTaskSwitchTimeTracker(task_switch_source);
   if (!task_switch_time_tracker)

ash/metrics/task_switch_metrics_recorder.h

@@ -27,6 +27,9 @@ class ASH_EXPORT TaskSwitchMetricsRecorder {
   // a task switch. Note this is not necessarily comprehensive of all sources.
   // TODO(bruthig): Convert enum format from kValue to VALUE.
   enum TaskSwitchSource {
+    // Task switches caused by any two sources in this enum. NOTE: This value
+    // should NOT be used outside of this class.
+    kAny,
     // Task switches from selecting items in the app list.
     kAppList,
     // Task switches caused by the user activating a task window by clicking or
@@ -46,19 +49,30 @@ class ASH_EXPORT TaskSwitchMetricsRecorder {
   TaskSwitchMetricsRecorder();
   virtual ~TaskSwitchMetricsRecorder();
 
-  // Notifies |this| that a "navigate to" task switch has occurred. A
-  // "navigate to" operation is defined by a task switch where the specific task
-  // that becomes active is user-predictable (ie 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
-  // (ie. closing or minimizing a window, closing a tab, etc).
+  // Notifies |this| that a "navigate to" task switch has occurred from the
+  // specified |task_switch_source|. The metrics associated with
+  // TaskSwitchSource::kAny source will be updated as well.
+  //
+  // NOTE: A |task_switch_source| value of TaskSwitchSource::kAny 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::kAny 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(

ash/metrics/task_switch_metrics_recorder_unittest.cc

@@ -62,6 +62,17 @@ void TaskSwitchMetricsRecorderTest::TearDown() {
 
 }  // namespace
 
+// Verifies that task switches from a non kAny source also add data to the
+// Ash.TimeBetweenTaskSwitches histogram.
+TEST_F(TaskSwitchMetricsRecorderTest,
+       VerifyTaskSwitchesRecordInAllTaskSwitchHistogram) {
+  const std::string kHistogramName = "Ash.TimeBetweenTaskSwitches";
+
+  OnTaskSwitch(TaskSwitchMetricsRecorder::kShelf);
+  OnTaskSwitch(TaskSwitchMetricsRecorder::kShelf);
+  histogram_tester_->ExpectTotalCount(kHistogramName, 1);
+}
+
 // Verifies that the TaskSwitchMetricsRecorder::kDesktop source adds data to the
 // Ash.Desktop.TimeBetweenNavigateToTaskSwitches histogram.
 TEST_F(TaskSwitchMetricsRecorderTest, VerifyTaskSwitchesForDesktopAreRecorded) {

tools/metrics/histograms/histograms.xml

@@ -860,6 +860,20 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
   </summary>
 </histogram>
 
+<histogram name="Ash.TimeBetweenTaskSwitches" units="seconds">
+  <owner>bruthig@google.com</owner>
+  <owner>tdanderson@google.com</owner>
+  <summary>
+    The number of seconds between contiguous task switch user actions triggered
+    by any of the other task switch actions that are tracked. (e.g.,
+    Ash.Shelf.TimeBetweenNavigateToTaskSwitches,
+    Ash.Tab.TimeBetweenSwitchToExistingTabUserActions,
+    Ash.WindowCycleController.TimeBetweenTaskSwitches,
+    Ash.AppList.TimeBetweenTaskSwitches,
+    Ash.WindowSelector.TimeBetweenActiveWindowChanges, etc).
+  </summary>
+</histogram>
+
 <histogram name="Ash.TouchDuration" units="milliseconds">
   <obsolete>
     Deprecated 12/2013 in r239809, and replaced by Ash.TouchDuration2.