ash:Shelf - Added UMA stats for ShelfAlignment

ash/periodic_metrics_recorder.cc

Index: ash/periodic_metrics_recorder.cc
diff --git a/ash/periodic_metrics_recorder.cc b/ash/periodic_metrics_recorder.cc
new file mode 100644
index 0000000000000000000000000000000000000000..40cb0b958fe3102aa708504e3df5eeba46803fd6
--- /dev/null
+++ b/ash/periodic_metrics_recorder.cc
@@ -0,0 +1,43 @@
+// Copyright (c) 2013 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/periodic_metrics_recorder.h"
+
+#include "ash/shelf/shelf_layout_manager.h"
+#include "ash/shelf/shelf_view.h"
+#include "ash/shelf/shelf_widget.h"
+#include "ash/shell.h"
+#include "base/metrics/histogram.h"
+
+namespace ash {
+
+// Time in seconds between calls to "RecordMetrics".
+const int kAshPeriodicMetricsTimeInSeconds = 30 * 60;
+
+PeriodicMetricsRecorder::PeriodicMetricsRecorder() {
+  timer_.Start(FROM_HERE,
+               base::TimeDelta::FromSeconds(kAshPeriodicMetricsTimeInSeconds),
+               this,
+               &PeriodicMetricsRecorder::RecordMetrics);
+}
+
+PeriodicMetricsRecorder::~PeriodicMetricsRecorder() {
+  timer_.Stop();
+}
+
+void PeriodicMetricsRecorder::RecordMetrics() {
+  internal::ShelfLayoutManager* manager =
+      internal::ShelfLayoutManager::ForLauncher(Shell::GetPrimaryRootWindow());
+  if (manager) {
+    UMA_HISTOGRAM_ENUMERATION("Ash.ShelfAlignmentOverTime",
+        manager->SelectValueForShelfAlignment(
+            internal::SHELF_ALIGNMENT_UMA_ENUM_VALUE_BOTTOM,
+            internal::SHELF_ALIGNMENT_UMA_ENUM_VALUE_LEFT,
+            internal::SHELF_ALIGNMENT_UMA_ENUM_VALUE_RIGHT,
+            -1),
+        internal::SHELF_ALIGNMENT_UMA_ENUM_VALUE_COUNT);
+  }
+}
+
+}  // namespace ash