Detect change on the intersection of video and viewport.

media/remoting/remoting_renderer_controller.h

 // 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 MEDIA_REMOTING_REMOTING_RENDERER_CONTROLLER_H_
 #define MEDIA_REMOTING_REMOTING_RENDERER_CONTROLLER_H_
 
 #include "base/callback.h"
 #include "base/memory/weak_ptr.h"
+#include "base/timer/timer.h"
 #include "media/base/media_observer.h"
 #include "media/remoting/remoting_source_impl.h"
 
 namespace media {
 
 namespace remoting {
 class RpcBroker;
 }
 
 // This class:
 // 1) Implements the RemotingSourceImpl::Client;
 // 2) Monitors player events as a MediaObserver;
 // 3) May trigger the switch of the media renderer between local playback
 // and remoting.
 class RemotingRendererController final : public RemotingSourceImpl::Client,
                                          public MediaObserver {
  public:
   explicit RemotingRendererController(
       scoped_refptr<RemotingSourceImpl> remoting_source);
   ~RemotingRendererController() override;
 
   // RemotingSourceImpl::Client implemenations.
   void OnStarted(bool success) override;
   void OnSessionStateChanged() override;
 
   // MediaObserver implementations.
   void OnEnteredFullscreen() override;
   void OnExitedFullscreen() override;
+  void OnVideoViewportIntersectionChanged(
+      const ViewportIntersectionInfo& info) override;
   void OnSetCdm(CdmContext* cdm_context) override;
   void OnMetadataChanged(const PipelineMetadata& metadata) override;
 
   void SetSwitchRendererCallback(const base::Closure& cb);
 
   base::WeakPtr<RemotingRendererController> GetWeakPtr() {
     return weak_factory_.GetWeakPtr();
   }
 
   // Used by RemotingRendererFactory to query whether to create Media Remoting
@@ skipping 35 matching lines @@
   bool IsVideoCodecSupported();
   bool IsAudioCodecSupported();
 
   // Helper to decide whether to enter or leave Remoting mode.
   bool ShouldBeRemoting();
 
   // Determines whether to enter or leave Remoting mode and switches if
   // necessary.
   void UpdateAndMaybeSwitch();
 
+  // Callback from |viewport_fill_debouncer_timer_| when video keeps covering
+  // most of the viewport for a certain time.
+  void OnViewportMostlyFilledAndUnchanging();
+
   // Indicates whether this media element or its ancestor is in full screen.
   bool is_fullscreen_ = false;
 
   // Indicates whether remoting is started.
   bool remote_rendering_started_ = false;
 
   // Indicates whether audio or video is encrypted.
   bool is_encrypted_ = false;
 
   // Current audio/video config.
   VideoDecoderConfig video_decoder_config_;
   AudioDecoderConfig audio_decoder_config_;
 
+  // Indicates whether video covers most of the viewport.
+  bool is_mostly_filling_viewport_ = false;
+
+  // Video/Viewport ratio meeting/exceeding the threshold should hold steady for
+  // a certain time before attempting to start remoting.
+  base::OneShotTimer viewport_fill_debouncer_timer_;
+
   // The callback to switch the media renderer.
   base::Closure switch_renderer_cb_;
 
   // This is initially the RemotingSourceImpl passed to the ctor, and might be
   // replaced with a different instance later if OnSetCdm() is called.
   scoped_refptr<RemotingSourceImpl> remoting_source_;
 
   // This is used to check all the methods are called on the current thread in
   // debug builds.
   base::ThreadChecker thread_checker_;
 
   PipelineMetadata pipeline_metadata_;
 
   base::WeakPtrFactory<RemotingRendererController> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(RemotingRendererController);
 };
 
 }  // namespace media
 
 #endif  // MEDIA_REMOTING_REMOTING_RENDERER_CONTROLLER_H_