[Android] Add AppMenu touch duration metric.

chrome/browser/android/appmenu/app_menu_drag_helper.cc

+// Copyright 2014 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 "base/metrics/histogram_macros.h"
+#include "chrome/browser/android/appmenu/app_menu_drag_helper.h"
+#include "jni/AppMenuDragHelper_jni.h"
+
+bool RegisterAppMenuDragHelper(JNIEnv* env) {
+  return RegisterNativesImpl(env);
+}
+
+// static
+void RecordAppMenuTouchDuration(JNIEnv* env, jclass jcaller, jlong time_ms) {
+  UMA_HISTOGRAM_TIMES("WrenchMenu.TouchDuration",
+                      base::TimeDelta::FromMilliseconds(time_ms));
+}