cast: Support for low-latency interactive mode

content/browser/media/capture/window_activity_tracker.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_H_
+#define CONTENT_BROWSER_MEDIA_CAPTURE_WINDOW_ACTIVITY_TRACKER_H_
+
+#include "base/macros.h"
+#include "base/memory/weak_ptr.h"
+#include "content/common/content_export.h"
+
+namespace content {
+
+// WindowActivityTracker is an interface that can be implememented to report
+// whether the user is actively interacting with UI.
+class CONTENT_EXPORT WindowActivityTracker {
+ public:
+  virtual ~WindowActivityTracker() {}
+
+  // Returns true if UI interaction is active.
+  virtual bool IsUiInteractionActive() const = 0;
+
+  // Resets any previous UI activity tracked.
+  virtual void Reset() = 0;
+
+  // Returns a weak pointer.
+  virtual base::WeakPtr<WindowActivityTracker> GetWeakPtr() = 0;
+};
+
+}  // namespace content
+
+#endif  // CONTENT_BROWSER_MEDIA_CAPTURE_WINDOW_ACTIVITY_TRACKER_H_