Enforce containing block requirement for IntersectionObserver.

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

 // 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 "core/dom/IntersectionObserver.h"
 
 #include "bindings/core/v8/ExceptionState.h"
 #include "core/css/parser/CSSParserTokenRange.h"
 #include "core/css/parser/CSSTokenizer.h"
 #include "core/dom/ExceptionCode.h"
@@ skipping 154 matching lines @@
 #endif
 
 LayoutObject* IntersectionObserver::rootLayoutObject() const
 {
     Node* node = rootNode();
     if (node->isDocumentNode())
         return toDocument(node)->layoutView();
     return toElement(node)->layoutObject();
 }
 
-bool IntersectionObserver::isDescendantOfRoot(const Element* target) const
-{
-    // Is m_root an ancestor, through the DOM and frame trees, of target?
-    Node* node = rootNode();
-    if (!node || !target || target == node)
-        return false;
-    if (!target->inDocument() || !node->inDocument())
-        return false;
-
-    Document* rootDocument = &node->document();
-    Document* targetDocument = &target->document();
-    while (targetDocument != rootDocument) {
-        target = targetDocument->ownerElement();
-        if (!target)
-            return false;
-        targetDocument = &target->document();
-    }
-    if (node->isDocumentNode()) {
-        ASSERT(targetDocument == node);
-        return true;
-    }
-    return target->isDescendantOf(node);
-}
-
 void IntersectionObserver::observe(Element* target, ExceptionState& exceptionState)
 {
     if (!m_root) {
         exceptionState.throwDOMException(HierarchyRequestError, "Invalid observer: root element or containing document has been deleted.");
         return;
     }
     if (!target) {
         exceptionState.throwTypeError("Observation target must be an element.");
         return;
     }
     if (m_root.get() == target) {
         exceptionState.throwDOMException(HierarchyRequestError, "Cannot use the same element for root and target.");
         return;
     }
-    if (!isDescendantOfRoot(target)) {
-        exceptionState.throwDOMException(HierarchyRequestError, "Observed element must be a descendant of the observer's root element.");
-        return;
-    }
 
     // TODO(szager): Add a pointer to the spec that describes this policy.
     bool shouldReportRootBounds = target->document().frame()->securityContext()->securityOrigin()->canAccess(rootNode()->document().frame()->securityContext()->securityOrigin());
     if (!shouldReportRootBounds && hasPercentMargin()) {
         exceptionState.throwDOMException(HierarchyRequestError, "Cannot observe a cross-origin target because the observer has a root margin value specified as a percent.");
         return;
     }
 
     if (target->ensureIntersectionObserverData().getObservationFor(*this))
         return;
 
     IntersectionObservation* observation = new IntersectionObservation(*this, *target, shouldReportRootBounds);
     target->ensureIntersectionObserverData().addObservation(*observation);
     m_observations.add(observation);
 }
 
 void IntersectionObserver::unobserve(Element* target, ExceptionState&)
 {
     if (!target || !target->intersectionObserverData())
         return;
     // TODO(szager): unobserve callback
     if (IntersectionObservation* observation = target->intersectionObserverData()->getObservationFor(*this))
         observation->disconnect();
 }
 
 void IntersectionObserver::computeIntersectionObservations()
 {
-    if (!m_root)
+    if (!m_root || !m_root->inDocument())
         return;
     Document* callbackDocument = toDocument(m_callback->executionContext());
     if (!callbackDocument)
         return;
     LocalDOMWindow* callbackDOMWindow = callbackDocument->domWindow();
     if (!callbackDOMWindow)
         return;
     DOMHighResTimeStamp timestamp = DOMWindowPerformance::performance(*callbackDOMWindow)->now();
     for (auto& observation : m_observations)
         observation->computeIntersectionObservations(timestamp);
@@ skipping 96 matching lines @@
 {
 
     if (m_entries.isEmpty())
         return;
 
     HeapVector<Member<IntersectionObserverEntry>> entries;
     entries.swap(m_entries);
     m_callback->handleEvent(entries, *this);
 }
 
-void IntersectionObserver::setActive(bool active)
-{
-    for (auto& observation : m_observations)
-        observation->setActive(m_root && active && isDescendantOfRoot(observation->target()));
-}
-
 bool IntersectionObserver::hasPercentMargin() const
 {
     return (m_topMargin.type() == Percent
         || m_rightMargin.type() == Percent
         || m_bottomMargin.type() == Percent
         || m_leftMargin.type() == Percent);
 }
 
 DEFINE_TRACE(IntersectionObserver)
 {
 #if ENABLE(OILPAN)
     visitor->template registerWeakMembers<IntersectionObserver, &IntersectionObserver::clearWeakMembers>(this);
 #endif
     visitor->trace(m_callback);
     visitor->trace(m_observations);
     visitor->trace(m_entries);
 }
 
 } // namespace blink