Notify WebMediaPlayer when its ancestor enters/exists fullscreen.

third_party/WebKit/Source/web/FullscreenController.cpp

 /*
  * Copyright (C) 2013 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 13 matching lines @@
  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
 #include "web/FullscreenController.h"
 
 #include "core/dom/Document.h"
+#include "core/dom/ElementTraversal.h"
 #include "core/dom/Fullscreen.h"
 #include "core/frame/FrameView.h"
 #include "core/frame/LocalFrame.h"
 #include "core/frame/PageScaleConstraintsSet.h"
 #include "core/html/HTMLMediaElement.h"
 #include "core/html/HTMLVideoElement.h"
 #include "core/layout/LayoutFullScreen.h"
 #include "platform/RuntimeEnabledFeatures.h"
 #include "public/platform/WebLayerTreeView.h"
 #include "public/web/WebFrameClient.h"
@@ skipping 35 matching lines @@
   }
 
   Fullscreen::from(document).didEnterFullscreenForElement(element);
   DCHECK_EQ(Fullscreen::currentFullScreenElementFrom(document), element);
 
   if (isHTMLVideoElement(element)) {
     HTMLVideoElement* videoElement = toHTMLVideoElement(element);
     if (videoElement->usesOverlayFullscreenVideo() &&
         m_webViewImpl->layerTreeView())
       m_webViewImpl->layerTreeView()->setHasTransparentBackground(true);
+  } else {
+    for (HTMLVideoElement& videoElement :
+         Traversal<HTMLVideoElement>::descendantsOf(*element)) {

[esprehn, 2016/10/11 21:40:04]

I still don't think we should land this. It requires traversing the entire
subtree of the full screen element, which can be a huge section of the page, for
example it's the entire presentation in Google Slides.

+      if (videoElement.webMediaPlayer() &&
+          videoElement.clientWidth() >=
+              videoElement.document().domWindow()->innerWidth() * 0.9 &&
+          videoElement.clientHeight() >=
+              videoElement.document().domWindow()->innerHeight() * 0.9) {
+        videoElement.webMediaPlayer()->enterFullWindow();
+        break;
+      }
+    }
   }
 }
 
 void FullscreenController::didExitFullscreen() {
   if (!m_fullscreenFrame)
     return;
 
   if (m_haveEnteredFullscreen)
     updatePageScaleConstraints(true);
 
@@ skipping 14 matching lines @@
           m_webViewImpl->layerTreeView()->setHasTransparentBackground(
               m_webViewImpl->isTransparent());
 
         // We need to wait until style and layout are updated in order
         // to propertly restore scroll offsets since content may not be
         // overflowing in the same way until they do.
         if (m_haveEnteredFullscreen)
           m_needsScrollAndScaleRestore = true;
 
         fullscreen->didExitFullscreen();
+
+        for (HTMLVideoElement& videoElement :
+             Traversal<HTMLVideoElement>::descendantsOf(*element)) {
+          if (videoElement.webMediaPlayer() &&
+              videoElement.webMediaPlayer()->isFullWindow()) {
+            videoElement.webMediaPlayer()->exitFullWindow();

[foolip, 2016/10/11 09:37:13]

Test and comment somewhere on what happens if the video element is removed from
the document. That won't exit fullscreen, but it should change the cast mode
back to plain tab mirroring.

[xjz, 2016/10/11 19:27:26]

The WebMediaPlayer get destroyed and the romoting session stopped if the video
element is removed from the document. One media remoting session is only with
one HTMLMediaElement. Other kind of contents will be always rendered locally.

There might be performance issue here as esprehn@ commented. If the video
element is removed from the document, or if there is no video element called
enterFullWindow(), all video descendants will be looked through.

+            break;
+          }
+        }
       }
     }
   }
 
   m_haveEnteredFullscreen = false;
   m_fullscreenFrame.clear();
 }
 
 void FullscreenController::enterFullscreenForElement(Element* element) {
   // We are already transitioning to fullscreen for a different element.
@@ skipping 100 matching lines @@
 
   m_webViewImpl->updateMainFrameLayoutSize();
 }
 
 DEFINE_TRACE(FullscreenController) {
   visitor->trace(m_provisionalFullscreenElement);
   visitor->trace(m_fullscreenFrame);
 }
 
 }  // namespace blink