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..2bfc89f46ed25eeaa5a4eb0e32cad56b89c43f41
--- /dev/null
+++ b/ash/periodic_metrics_recorder.cc
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+// 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_widget.h"
+#include "ash/shell.h"
+#include "base/metrics/histogram.h"
+
+namespace ash {
+namespace {
+const int SHELF_ALIGNMENT_UMA_ENUM_VALUE_BOTTOM = 0;
+const int SHELF_ALIGNMENT_UMA_ENUM_VALUE_LEFT = 1;
+const int SHELF_ALIGNMENT_UMA_ENUM_VALUE_RIGHT = 2;
+const int SHELF_ALIGNMENT_UMA_ENUM_VALUE_COUNT = 3;
+}
+
+// Time in seconds between calls to "RecordMetrics".
+const int kAshPeriodicMetricsTimeInSeconds = 30 * 60;
+
+AshPeriodicMetricsRecorder::AshPeriodicMetricsRecorder() {
+  timer_.Start(FROM_HERE,
+               base::TimeDelta::FromSeconds(kAshPeriodicMetricsTimeInSeconds),
+               this,
+               &AshPeriodicMetricsRecorder::RecordMetrics);
+}
+
+AshPeriodicMetricsRecorder::~AshPeriodicMetricsRecorder() {
+  timer_.Stop();
+}
+
+void AshPeriodicMetricsRecorder::RecordMetrics() {
+  internal::ShelfLayoutManager* manager =
+      internal::ShelfLayoutManager::ForLauncher(Shell::GetPrimaryRootWindow());
+  if (manager) {
+    UMA_HISTOGRAM_ENUMERATION("Ash.ShelfAlignmentOverTime",
+        manager->SelectValueForShelfAlignment(
+            SHELF_ALIGNMENT_UMA_ENUM_VALUE_BOTTOM,
+            SHELF_ALIGNMENT_UMA_ENUM_VALUE_LEFT,
+            SHELF_ALIGNMENT_UMA_ENUM_VALUE_RIGHT,
+            -1),
+        SHELF_ALIGNMENT_UMA_ENUM_VALUE_COUNT);
+  }
+}
+
+}  // namespace ash