UMA stats for stylus usage

ash/metrics/pointer_metrics_recorder.cc

Index: ash/metrics/pointer_metrics_recorder.cc
diff --git a/ash/metrics/pointer_metrics_recorder.cc b/ash/metrics/pointer_metrics_recorder.cc
new file mode 100644
index 0000000000000000000000000000000000000000..b48e9845940a0cac50a1be83d46823c29353cbaa
--- /dev/null
+++ b/ash/metrics/pointer_metrics_recorder.cc
@@ -0,0 +1,108 @@
+// Copyright 2016 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.
+
+#include "ash/metrics/pointer_metrics_recorder.h"
+
+#include "ash/common/wm/maximize_mode/maximize_mode_controller.h"
+#include "ash/common/wm_lookup.h"
+#include "ash/common/wm_shell.h"
+#include "ash/common/wm_window.h"
+#include "ash/shared/app_types.h"
+#include "base/metrics/histogram_macros.h"
+#include "ui/aura/client/aura_constants.h"
+#include "ui/events/event_constants.h"
+#include "ui/views/widget/widget.h"
+
+namespace ash {
+
+namespace {
+
+// Form factor of the down event. This enum is used to back an UMA histogram
+// and should be treated as append-only.
+enum class DownEventFormFactor {
+  CLAM_SHELL = 0,

[Daniel Erat, 2016/09/27 19:15:10]

nit: "CLAMSHELL" instead of "CLAM_SHELL" (since it's usually written as a single
word; see e.g. https://en.wikipedia.org/wiki/Clamshell_(container) )

[xiaoyinh(OOO Sep 11-29), 2016/09/29 20:37:43]

Done.

+  TOUCH_VIEW,
+  FORM_FACTOR_COUNT,
+};
+
+// Input type of the down event. This enum is used to back an UMA
+// histogram and should be treated as append-only.
+enum class DownEventSource {
+  UNKNOWN = 0,
+  MOUSE,
+  STYLUS,
+  TOUCH,
+  SOURCE_COUNT,
+};
+
+void RecordUMA(ui::EventPointerType type, views::Widget* target) {
+  DownEventFormFactor form_factor = DownEventFormFactor::CLAM_SHELL;
+  if (ash::WmShell::Get()
+          ->maximize_mode_controller()
+          ->IsMaximizeModeWindowManagerEnabled()) {
+    form_factor = DownEventFormFactor::TOUCH_VIEW;
+  }
+  UMA_HISTOGRAM_ENUMERATION(
+      "Event.DownEventCount.PerFormFactor",
+      static_cast<base::HistogramBase::Sample>(form_factor),
+      static_cast<base::HistogramBase::Sample>(
+          DownEventFormFactor::FORM_FACTOR_COUNT));
+
+  DownEventSource input_type = DownEventSource::UNKNOWN;
+  switch (type) {
+    case ui::EventPointerType::POINTER_TYPE_UNKNOWN:
+      input_type = DownEventSource::UNKNOWN;
+      break;
+    case ui::EventPointerType::POINTER_TYPE_MOUSE:
+      input_type = DownEventSource::MOUSE;
+      break;
+    case ui::EventPointerType::POINTER_TYPE_PEN:
+      input_type = DownEventSource::STYLUS;
+      break;
+    case ui::EventPointerType::POINTER_TYPE_TOUCH:
+      input_type = DownEventSource::TOUCH;
+      break;
+    case ui::EventPointerType::POINTER_TYPE_ERASER:
+      input_type = DownEventSource::STYLUS;
+      break;
+  }
+
+  UMA_HISTOGRAM_ENUMERATION(
+      "Event.DownEventCount.PerInput",
+      static_cast<base::HistogramBase::Sample>(input_type),
+      static_cast<base::HistogramBase::Sample>(DownEventSource::SOURCE_COUNT));
+
+  if (!target)
+    return;
+
+  aura::Window* window = target->GetNativeWindow();
+  DCHECK(window);
+
+  int window_type = window->GetProperty(aura::client::kAppType);
+  UMA_HISTOGRAM_ENUMERATION(
+      "Event.DownEventCount.PerDestination", window_type,
+      static_cast<base::HistogramBase::Sample>(AppType::APP_COUNT));
+}
+
+}  // namespace
+
+PointerMetricsRecorder::PointerMetricsRecorder() {
+  ash::WmShell::Get()->AddPointerWatcher(
+      this, views::PointerWatcherEventTypes::BASIC);
+}
+
+PointerMetricsRecorder::~PointerMetricsRecorder() {
+  ash::WmShell::Get()->RemovePointerWatcher(this);
+}
+
+void PointerMetricsRecorder::OnPointerEventObserved(
+    const ui::PointerEvent& event,
+    const gfx::Point& location_in_screen,
+    views::Widget* target) {
+  if (event.type() != ui::ET_POINTER_DOWN)
+    return;
+  RecordUMA(event.pointer_details().pointer_type, target);
+}
+
+}  // namespace ash