Media Remoting: Add interstitial elements to media element shadow dom.

third_party/WebKit/Source/core/html/HTMLMediaElement.cpp

Index: third_party/WebKit/Source/core/html/HTMLMediaElement.cpp
diff --git a/third_party/WebKit/Source/core/html/HTMLMediaElement.cpp b/third_party/WebKit/Source/core/html/HTMLMediaElement.cpp
index aba444552a10ad8c40c4d51f4bace25aa00ea1fd..d8be96ee29478986bc45cda7975ec231421b29e0 100644
--- a/third_party/WebKit/Source/core/html/HTMLMediaElement.cpp
+++ b/third_party/WebKit/Source/core/html/HTMLMediaElement.cpp
@@ -3562,19 +3562,31 @@ bool HTMLMediaElement::textTracksVisible() const {
   return m_textTracksVisible;
 }
 
-static void assertShadowRootChildren(ShadowRoot& shadowRoot) {
+// static
+void HTMLMediaElement::assertShadowRootChildren(ShadowRoot& shadowRoot) {
 #if DCHECK_IS_ON()
-  // There can be up to two children, either or both of the text
-  // track container and media controls. If both are present, the
-  // text track container must be the first child.
+  // There can be up to three children: media remoting interstitial, text track
+  // container, media controls. The mediaControls has to be the last child if
+  // present, and has to be the next sibling of the text track container if both
+  // present.
   unsigned numberOfChildren = shadowRoot.countChildren();
-  DCHECK_LE(numberOfChildren, 2u);
+  DCHECK_LE(numberOfChildren, 3u);
   Node* firstChild = shadowRoot.firstChild();
   Node* lastChild = shadowRoot.lastChild();
   if (numberOfChildren == 1) {
-    DCHECK(firstChild->isTextTrackContainer() || firstChild->isMediaControls());
+    DCHECK(firstChild->isTextTrackContainer() ||
+           firstChild->isMediaControls() ||
+           firstChild->isMediaRemotingInterstitial());
   } else if (numberOfChildren == 2) {
-    DCHECK(firstChild->isTextTrackContainer());
+    DCHECK(firstChild->isTextTrackContainer() ||
+           firstChild->isMediaRemotingInterstitial());
+    DCHECK(lastChild->isTextTrackContainer() || lastChild->isMediaControls());
+    if (firstChild->isTextTrackContainer())
+      DCHECK(lastChild->isMediaControls());
+  } else if (numberOfChildren == 3) {
+    Node* secondChild = firstChild->nextSibling();
+    DCHECK(firstChild->isMediaRemotingInterstitial());
+    DCHECK(secondChild->isTextTrackContainer());
     DCHECK(lastChild->isMediaControls());
   }
 #endif
@@ -3587,13 +3599,21 @@ TextTrackContainer& HTMLMediaElement::ensureTextTrackContainer() {
   Node* firstChild = shadowRoot.firstChild();
   if (firstChild && firstChild->isTextTrackContainer())
     return toTextTrackContainer(*firstChild);
+  Node* toBeInsertedBefore = firstChild;
+
+  if (firstChild->isMediaRemotingInterstitial()) {
+    Node* secondChild = firstChild->nextSibling();
+    if (secondChild && secondChild->isTextTrackContainer())
+      return toTextTrackContainer(*secondChild);
+    toBeInsertedBefore = secondChild;
+  }
 
   TextTrackContainer* textTrackContainer =
       TextTrackContainer::create(document());
 
   // The text track container should be inserted before the media controls,
   // so that they are rendered behind them.
-  shadowRoot.insertBefore(textTrackContainer, firstChild);
+  shadowRoot.insertBefore(textTrackContainer, toBeInsertedBefore);
 
   assertShadowRootChildren(shadowRoot);