Monitor the intersection of video and viewport.

third_party/WebKit/Source/core/dom/IntersectionObserver.cpp

Index: third_party/WebKit/Source/core/dom/IntersectionObserver.cpp
diff --git a/third_party/WebKit/Source/core/dom/IntersectionObserver.cpp b/third_party/WebKit/Source/core/dom/IntersectionObserver.cpp
index 32ef04c78978b5f0856a4812c1ff8499585d1e5d..5154c7e535ac863d6c8e65bc425d7c5ec01eba71 100644
--- a/third_party/WebKit/Source/core/dom/IntersectionObserver.cpp
+++ b/third_party/WebKit/Source/core/dom/IntersectionObserver.cpp
@@ -169,7 +169,8 @@ IntersectionObserver* IntersectionObserver::create(
   if (exceptionState.hadException())
     return nullptr;
 
-  return new IntersectionObserver(callback, *root, rootMargin, thresholds);
+  return new IntersectionObserver(callback, *root, rootMargin, thresholds,
+                                  false);
 }
 
 IntersectionObserver* IntersectionObserver::create(
@@ -189,14 +190,34 @@ IntersectionObserver* IntersectionObserver::create(
   IntersectionObserverCallbackImpl* intersectionObserverCallback =
       new IntersectionObserverCallbackImpl(document, std::move(callback));
   return new IntersectionObserver(*intersectionObserverCallback, *root,
-                                  rootMargin, thresholds);
+                                  rootMargin, thresholds, false);
+}
+
+IntersectionObserver* IntersectionObserver::create(
+    const Vector<Length>& rootMargin,
+    Document* document,
+    std::unique_ptr<EventCallback> callback,
+    ExceptionState& exceptionState) {
+  Node* root = getRootNode(document);
+  if (!root) {
+    exceptionState.throwDOMException(
+        HierarchyRequestError,
+        "Unable to get root node in main frame to track.");
+    return nullptr;
+  }
+
+  IntersectionObserverCallbackImpl* intersectionObserverCallback =
+      new IntersectionObserverCallbackImpl(document, std::move(callback));
+  return new IntersectionObserver(*intersectionObserverCallback, *root,
+                                  rootMargin, Vector<float>(), true);
 }
 
 IntersectionObserver::IntersectionObserver(
     IntersectionObserverCallback& callback,
     Node& root,
     const Vector<Length>& rootMargin,
-    const Vector<float>& thresholds)
+    const Vector<float>& thresholds,
+    bool isObservingRatio)
     : m_callback(&callback),
       m_root(&root),
       m_thresholds(thresholds),
@@ -204,7 +225,8 @@ IntersectionObserver::IntersectionObserver(
       m_rightMargin(Fixed),
       m_bottomMargin(Fixed),
       m_leftMargin(Fixed),
-      m_initialState(InitialState::kHidden) {
+      m_initialState(InitialState::kHidden),
+      m_observeElementViewportRatio(isObservingRatio) {
   switch (rootMargin.size()) {
     case 0:
       break;
@@ -269,7 +291,9 @@ void IntersectionObserver::observe(Element* target,
   LocalFrame* targetFrame = target->document().frame();
   LocalFrame* rootFrame = m_root->document().frame();
 
-  if (target->document() == rootNode()->document()) {
+  if (m_observeElementViewportRatio) {
+    shouldReportRootBounds = true;
+  } else if (target->document() == rootNode()->document()) {
     shouldReportRootBounds = true;
     isDOMDescendant = rootNode()->isShadowIncludingInclusiveAncestorOf(target);
   } else if (targetFrame && rootFrame) {
@@ -279,8 +303,13 @@ void IntersectionObserver::observe(Element* target,
     isDOMDescendant = (targetFrame->tree().top() == rootFrame);
   }
 
-  IntersectionObservation* observation =
-      new IntersectionObservation(*this, *target, shouldReportRootBounds);
+  IntersectionObservation* observation;
+  if (m_observeElementViewportRatio) {
+    observation = new IntersectViewportRatioObservation(*this, *target);
+  } else {
+    observation =
+        new IntersectionObservation(*this, *target, shouldReportRootBounds);
+  }
   target->ensureIntersectionObserverData().addObservation(*observation);
   m_observations.add(observation);