Added UMA statistics for changing the active window via click or touch events.

ash/metrics/task_switch_metrics_recorder.cc

Index: ash/metrics/task_switch_metrics_recorder.cc
diff --git a/ash/metrics/task_switch_metrics_recorder.cc b/ash/metrics/task_switch_metrics_recorder.cc
index b8b57fe4753606428c68f2be1236c100070d10c9..25c892b78cd3b74d94bb95c0ece296ddf1795518 100644
--- a/ash/metrics/task_switch_metrics_recorder.cc
+++ b/ash/metrics/task_switch_metrics_recorder.cc
@@ -5,11 +5,16 @@
 #include "ash/metrics/task_switch_metrics_recorder.h"
 
 #include "ash/metrics/task_switch_time_tracker.h"
+#include "ui/aura/window.h"
+#include "ui/wm/public/window_types.h"
 
 namespace ash {
 
 namespace {
 
+const char kScreenHistogramName[] =
+    "Ash.Screen.TimeBetweenNavigateToTaskSwitches";

[tdanderson, 2015/05/26 21:13:52]

don't forget to update histograms.xml

[bruthig, 2015/06/03 21:59:31]

Done.

+
 const char kShelfHistogramName[] =
     "Ash.Shelf.TimeBetweenNavigateToTaskSwitches";
 
@@ -32,6 +37,8 @@ const char* GetHistogramName(
       return kAppListHistogramName;
     case TaskSwitchMetricsRecorder::kOverviewMode:
       return kOverviewModeHistogramName;
+    case TaskSwitchMetricsRecorder::kScreen:
+      return kScreenHistogramName;
     case TaskSwitchMetricsRecorder::kShelf:
       return kShelfHistogramName;
     case TaskSwitchMetricsRecorder::kTabStrip:
@@ -64,6 +71,11 @@ void TaskSwitchMetricsRecorder::OnTaskSwitch(
   task_switch_time_tracker->OnTaskSwitch();
 }
 
+bool TaskSwitchMetricsRecorder::IsATaskWindow(aura::Window* window) const {
+  return window && (window->type() == ui::wm::WINDOW_TYPE_NORMAL ||

[tdanderson, 2015/05/26 21:13:52]

It might be nice to define this as a static utility function somewhere in
ash/wm. Six other places in the code perform this same check, and they could
instead call into the utility function:

* CanHandleWindowSnapOrDock() in accelerator_controller.cc

* RootWindowController::GetWindowForFullscreenMode()

* DragWindowResizer::ShouldAllowMouseWarp()

* WindowSelector::IsSelectable()

...and be sure to dust off your notes from logic class because you'll be needing
DeMorgan's law for the last two:

* WindowWatcher::OnWindowAdded()

* DefaultState::ProcessWorkspaceEvents()

The benefit here is not just saving ~6 lines of code, but in naming the utility
function to describe a unique characteristic of windows which are normal or
panel types. One suggestion is IsWindowUserPositionable() but perhaps that isn't
the best. Whatever name you pick can be used in place of "task window".

[bruthig, 2015/06/03 21:59:31]

Done.

+                    window->type() == ui::wm::WINDOW_TYPE_PANEL);
+}
+
 TaskSwitchTimeTracker* TaskSwitchMetricsRecorder::FindTaskSwitchTimeTracker(
     TaskSwitchSource task_switch_source) {
   return histogram_map_.get(task_switch_source);