Media Remoting: Add RemotingController.

third_party/WebKit/Source/web/FullscreenController.cpp

Index: third_party/WebKit/Source/web/FullscreenController.cpp
diff --git a/third_party/WebKit/Source/web/FullscreenController.cpp b/third_party/WebKit/Source/web/FullscreenController.cpp
index cb8efeffd7bb3e843c17fa3f5debc2591e0afc5f..7a341fddc3bc803f0ee6d62fa188ce4f4145b278 100644
--- a/third_party/WebKit/Source/web/FullscreenController.cpp
+++ b/third_party/WebKit/Source/web/FullscreenController.cpp
@@ -31,6 +31,7 @@
 #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"
@@ -86,6 +87,12 @@ void FullscreenController::didEnterFullscreen() {
     if (videoElement->usesOverlayFullscreenVideo() &&
         m_webViewImpl->layerTreeView())
       m_webViewImpl->layerTreeView()->setHasTransparentBackground(true);
+  } else {
+    for (HTMLVideoElement& videoElement :
+         Traversal<HTMLVideoElement>::descendantsOf(*element)) {

[esprehn, 2016/10/08 03:33:04]

This is traversing every element of the element which just went full screen, I
don't think we want to do that, also this doesn't handle Shadow DOM, what are
you trying to do here?

[foolip, 2016/10/10 08:35:22]

I believe the idea is to detect a case where the video is the only thing visible
and switch to the other mode, but I think CL will do it even if there are
multiple videos in fullscreen, a single video as part of a presentation, and
perhaps other cases.

I was in an email thread about this, but I don't think I understand all of the
constraints. It seems that it needs to integrate with some or all of layout,
paint and compositing, perhaps something similar to the code using
HTMLVideoElement::usesOverlayFullscreenVideo.

Detecting this as part of layout should mean that the case where the video
element is the fullscreen element or one of the descendants could be treated the
same, all that matters is that there's nothing obscuring it.

[foolip, 2016/10/10 08:39:08]

Please make sure to write tests that show the behavior both for when the logic
should kick in and some of the cases where it shouldn't, which I hope would
include the case where there's a lot of stuff covering the video and where the
video doesn't cover most of the screen.

[xjz, 2016/10/10 19:31:02]

Removed this from this CL. As commented, will open a new CL for all full screen
related changes.

+      if (videoElement.webMediaPlayer())
+        videoElement.webMediaPlayer()->ancestorEnteredFullscreen();
+    }
   }
 }
 
@@ -120,6 +127,13 @@ void FullscreenController::didExitFullscreen() {
           m_needsScrollAndScaleRestore = true;
 
         fullscreen->didExitFullscreen();
+        if (!isHTMLVideoElement(element)) {
+          for (HTMLVideoElement& videoElement :
+               Traversal<HTMLVideoElement>::descendantsOf(*element)) {

[esprehn, 2016/10/08 03:33:04]

ditto, walking the entire document seems unfortunate, why do we need this
callback?

[xjz, 2016/10/10 19:31:02]

Removed this from this CL. As commented, will open a new CL for all full screen
related changes.

+            if (videoElement.webMediaPlayer())
+              videoElement.webMediaPlayer()->ancestorExitedFullscreen();
+          }
+        }
       }
     }
   }