IntersectionObserverCallbackImpl should use Member<ExecutionContext>

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 eade5171943781f148713d6be880359e56c06682..5dc179ae350bbd66009dd9a5bb19d467b3400d3b 100644
--- a/third_party/WebKit/Source/core/dom/IntersectionObserver.cpp
+++ b/third_party/WebKit/Source/core/dom/IntersectionObserver.cpp
@@ -54,7 +54,7 @@ class IntersectionObserverCallbackImpl final
   }
 
  private:
-  WeakMember<ExecutionContext> m_context;
+  Member<ExecutionContext> m_context;

[sof, 2016/12/26 07:28:04]

The use of WeakMember<> comes from


https://codereview.chromium.org/2051253002/diff/100001/third_party/WebKit/Sou...

not much discussion associated with it. If there are problems here with keeping
a strong reference, they'd be leaks.

   std::unique_ptr<IntersectionObserver::EventCallback> m_callback;
 };
 
@@ -222,7 +222,6 @@ bool IntersectionObserver::rootIsValid() const {
 Document& IntersectionObserver::trackingDocument() const {
   Document* document = nullptr;
   if (rootIsImplicit()) {
-    DCHECK(m_callback->getExecutionContext());
     document = toDocument(m_callback->getExecutionContext());
   } else {
     DCHECK(root());
@@ -310,10 +309,8 @@ void IntersectionObserver::unobserve(Element* target,
 void IntersectionObserver::computeIntersectionObservations() {
   if (!rootIsValid())
     return;
-  Document* callbackDocument = toDocument(m_callback->getExecutionContext());
-  if (!callbackDocument)
-    return;
-  LocalDOMWindow* callbackDOMWindow = callbackDocument->domWindow();
+  LocalDOMWindow* callbackDOMWindow =
+      toDocument(m_callback->getExecutionContext())->domWindow();
   if (!callbackDOMWindow)
     return;
   DOMHighResTimeStamp timestamp =