Make UserActivityDetector a singleton

ui/wm/core/user_activity_detector.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 "ui/wm/core/user_activity_detector.h"
 
 #include "base/format_macros.h"
 #include "base/logging.h"
 #include "base/strings/stringprintf.h"
 #include "ui/events/event.h"
 #include "ui/wm/core/user_activity_observer.h"
 
 namespace wm {
 
 namespace {
 
+UserActivityDetector* g_instance = NULL;

[oshima, 2014/10/31 16:53:31]

My preference is no g_ for file scoped variable as it's for global scoepd
variable, but i'll leave this to owners.

+
 // Returns a string describing |event|.
 std::string GetEventDebugString(const ui::Event* event) {
   std::string details = base::StringPrintf(
       "type=%d name=%s flags=%d time=%" PRId64,
       event->type(), event->name().c_str(), event->flags(),
       event->time_stamp().InMilliseconds());
 
   if (event->IsKeyEvent()) {
     details += base::StringPrintf(" key_code=%d",
         static_cast<const ui::KeyEvent*>(event)->key_code());
   } else if (event->IsMouseEvent() || event->IsTouchEvent() ||
              event->IsGestureEvent()) {
     details += base::StringPrintf(" location=%s",
         static_cast<const ui::LocatedEvent*>(
             event)->location().ToString().c_str());
   }
 
   return details;
 }
 
 }  // namespace
 
 const int UserActivityDetector::kNotifyIntervalMs = 200;
 
 // Too low and mouse events generated at the tail end of reconfiguration
 // will be reported as user activity and turn the screen back on; too high
 // and we'll ignore legitimate activity.
 const int UserActivityDetector::kDisplayPowerChangeIgnoreMouseMs = 1000;
 
-UserActivityDetector::UserActivityDetector() {
+// static
+void UserActivityDetector::Create() {
+  CHECK(!g_instance);
+  g_instance = new UserActivityDetector();

[oshima, 2014/10/31 16:53:31]

Initialize in ctor/dtor.

 }
 
-UserActivityDetector::~UserActivityDetector() {
+// static
+void UserActivityDetector::Shutdown() {
+  CHECK(g_instance);
+  delete g_instance;
+  g_instance = NULL;
+}
+
+// static
+UserActivityDetector* UserActivityDetector::Get() {
+  return g_instance;
 }
 
 bool UserActivityDetector::HasObserver(UserActivityObserver* observer) const {
   return observers_.HasObserver(observer);
 }
 
 void UserActivityDetector::AddObserver(UserActivityObserver* observer) {
   observers_.AddObserver(observer);
 }
 
@@ skipping 25 matching lines @@
 }
 
 void UserActivityDetector::OnTouchEvent(ui::TouchEvent* event) {
   HandleActivity(event);
 }
 
 void UserActivityDetector::OnGestureEvent(ui::GestureEvent* event) {
   HandleActivity(event);
 }
 
+UserActivityDetector::UserActivityDetector() {
+}
+
+UserActivityDetector::~UserActivityDetector() {
+}
+
 base::TimeTicks UserActivityDetector::GetCurrentTime() const {
   return !now_for_test_.is_null() ? now_for_test_ : base::TimeTicks::Now();
 }
 
 void UserActivityDetector::HandleActivity(const ui::Event* event) {
   base::TimeTicks now = GetCurrentTime();
   last_activity_time_ = now;
   if (last_observer_notification_time_.is_null() ||
       (now - last_observer_notification_time_).InMillisecondsF() >=
       kNotifyIntervalMs) {
     if (VLOG_IS_ON(1))
       VLOG(1) << "Reporting user activity: " << GetEventDebugString(event);
     FOR_EACH_OBSERVER(UserActivityObserver, observers_, OnUserActivity(event));
     last_observer_notification_time_ = now;
   }
 }
 
 }  // namespace wm