cast: Support for low-latency interactive mode

content/browser/media/capture/window_activity_tracker_aura.h

+// Copyright (c) 2015 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.
+
+#ifndef CONTENT_BROWSER_MEDIA_CAPTURE_WINDOW_ACTIVITY_TRACKER_AURA_H_
+#define CONTENT_BROWSER_MEDIA_CAPTURE_WINDOW_ACTIVITY_TRACKER_AURA_H_
+
+#include "base/macros.h"
+#include "base/memory/ref_counted.h"
+#include "base/memory/weak_ptr.h"
+#include "content/browser/media/capture/window_activity_tracker.h"
+#include "content/common/content_export.h"
+#include "ui/aura/window.h"
+#include "ui/events/event_handler.h"
+
+namespace content {
+
+// Tracks UI events and makes a decision on whether the user has been
+// actively interacting with a specified window.
+class CONTENT_EXPORT WindowActivityTrackerAura : public WindowActivityTracker,
+                                                 public ui::EventHandler,
+                                                 public aura::WindowObserver {
+ public:
+  explicit WindowActivityTrackerAura(aura::Window* window);
+  ~WindowActivityTrackerAura() final;
+
+  // WindowActivityTracker overrides.
+  bool IsUiInteractionActive() const final;
+  void Reset() final;
+  base::WeakPtr<WindowActivityTracker> GetWeakPtr() final;
+
+ private:
+  // ui::EventHandler overrides.
+  void OnEvent(ui::Event* event) final;
+
+  // aura::WindowObserver overrides.
+  void OnWindowDestroying(aura::Window* window) final;
+
+  aura::Window* window_;
+
+  // The last time a UI event was detected.
+  base::TimeTicks last_time_ui_event_detected_;
+
+  // The number of UI events detected so far. In case of continuous events
+  // such as mouse movement, a single continuous movement is treated
+  // as one event.
+  int ui_events_count_;
+
+  base::WeakPtrFactory<WindowActivityTrackerAura> weak_factory_;
+
+  DISALLOW_COPY_AND_ASSIGN(WindowActivityTrackerAura);
+};
+
+}  // namespace content
+
+#endif  // CONTENT_BROWSER_MEDIA_CAPTURE_WINDOW_ACTIVITY_TRACKER_AURA_H_