Detect change on the intersection of video and viewport.

media/remoting/remoting_renderer_controller.cc

 // 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.
 
 #include "media/remoting/remoting_renderer_controller.h"
 
 #include "base/bind.h"
 #include "base/logging.h"
 #include "base/threading/thread_checker.h"
 #include "media/remoting/remoting_cdm_context.h"
@@ skipping 42 matching lines @@
   UpdateAndMaybeSwitch();
 }
 
 void RemotingRendererController::OnExitedFullscreen() {
   DCHECK(thread_checker_.CalledOnValidThread());
 
   is_fullscreen_ = false;
   UpdateAndMaybeSwitch();
 }
 
+void RemotingRendererController::OnBecameDominantVisibleContent(
+    bool is_dominant) {
+  DCHECK(thread_checker_.CalledOnValidThread());
+  is_dominant_content_ = is_dominant;
+  UpdateAndMaybeSwitch();
+}
+
 void RemotingRendererController::OnSetCdm(CdmContext* cdm_context) {
   DCHECK(thread_checker_.CalledOnValidThread());
 
   auto* remoting_cdm_context = RemotingCdmContext::From(cdm_context);
   if (!remoting_cdm_context)
     return;
 
   remoting_source_->RemoveClient(this);
   remoting_source_ = remoting_cdm_context->GetRemotingSource();
   remoting_source_->AddClient(this);  // Calls OnSessionStateChanged().
@@ skipping 135 matching lines @@
 
   if ((!has_audio() && !has_video()) ||
       (has_video() && !IsVideoCodecSupported()) ||
       (has_audio() && !IsAudioCodecSupported())) {
     return false;
   }
 
   if (is_remote_playback_disabled_)
     return false;
 
-  // Normally, entering fullscreen is the signal that starts remote rendering.
-  // However, current technical limitations require encrypted content be remoted
-  // without waiting for a user signal.
-  return is_fullscreen_;
+  // Normally, entering fullscreen or being the dominant visible content is the
+  // signal that starts remote rendering. However, current technical limitations
+  // require encrypted content be remoted without waiting for a user signal.
+  return is_fullscreen_ || is_dominant_content_;
 }
 
 void RemotingRendererController::UpdateAndMaybeSwitch() {
   DCHECK(thread_checker_.CalledOnValidThread());
 
   bool should_be_remoting = ShouldBeRemoting();
 
   if (remote_rendering_started_ == should_be_remoting)
     return;
 
@@ skipping 15 matching lines @@
     // and never back to the local renderer. The RemotingCdmController will
     // force-stop the session when remoting has ended; so no need to call
     // StopRemoting() from here.
     DCHECK(!is_encrypted_);
     switch_renderer_cb_.Run();
     remoting_source_->StopRemoting(this);
   }
 }
 
 }  // namespace media