cast: Add window activity tracker for mac

This adds window activity detector for mac which enables the following
features to be enabled on tab mirroring:

- Low latency interactive mode will be turned on when user is
  interactive with non-animating content

- Frame subscriber will enable frame capture in response to mouse
  events resulting in smooth rendering of mouse while mirroring

BUG=567735

Review URL: https://codereview.chromium.org/1835493002

Cr-Commit-Position: refs/heads/master@{#383431}

1 files changed, 62 insertions, 0 deletions

diff --git a/content/browser/media/capture/window_activity_tracker_mac.h b/content/browser/media/capture/window_activity_tracker_mac.h
new file mode 100644
index 0000000..64c91a0
--- /dev/null
+++ b/content/browser/media/capture/window_activity_tracker_mac.h
@@ -0,0 +1,62 @@
+// Copyright 2016 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_MAC_H_
+#define CONTENT_BROWSER_MEDIA_CAPTURE_WINDOW_ACTIVITY_TRACKER_MAC_H_
+
+#import <AppKit/AppKit.h>
+#import <CoreFoundation/CoreFoundation.h>
+
+#include "base/callback.h"
+#include "base/mac/scoped_nsobject.h"
+#include "base/macros.h"
+#include "base/memory/weak_ptr.h"
+#include "content/browser/media/capture/window_activity_tracker.h"
+#include "content/common/content_export.h"
+#include "ui/base/cocoa/tracking_area.h"
+#include "ui/gfx/native_widget_types.h"
+
+@interface MouseTracker : NSObject {
+ @private
+  ui::ScopedCrTrackingArea trackingArea_;
+
+  // The view on which mouse movement is detected.
+  NSView* nsView_;
+
+  // Runs on any mouse interaction from user.
+  base::Closure mouseInteractionObserver_;
+}
+
+- (instancetype)initWithView:(NSView*)nsView;
+
+// Register an observer for mouse interaction.
+- (void)registerMouseInteractionObserver:(const base::Closure&)observer;
+
+@end
+
+namespace content {
+
+// Tracks UI events and makes a decision on whether the user has been
+// actively interacting with a specified window.
+class CONTENT_EXPORT WindowActivityTrackerMac : public WindowActivityTracker {
+ public:
+  explicit WindowActivityTrackerMac(NSView* view);
+  ~WindowActivityTrackerMac() final;
+
+  base::WeakPtr<WindowActivityTracker> GetWeakPtr() final;
+
+ private:
+  void OnMouseActivity();
+
+  NSView* const view_;
+  base::scoped_nsobject<MouseTracker> mouse_tracker_;
+
+  base::WeakPtrFactory<WindowActivityTrackerMac> weak_factory_;
+
+  DISALLOW_COPY_AND_ASSIGN(WindowActivityTrackerMac);
+};
+
+}  // namespace content
+
+#endif  // CONTENT_BROWSER_MEDIA_CAPTURE_WINDOW_ACTIVITY_TRACKER_MAC_H_