Remove ActiveDOMObject::stop()

third_party/WebKit/Source/modules/presentation/PresentationAvailability.cpp

Index: third_party/WebKit/Source/modules/presentation/PresentationAvailability.cpp
diff --git a/third_party/WebKit/Source/modules/presentation/PresentationAvailability.cpp b/third_party/WebKit/Source/modules/presentation/PresentationAvailability.cpp
index 584ef4cabfba599b3b43f8b79d2f1230fd50a579..6393482b49999f5d941373e14caa996d1409a731 100644
--- a/third_party/WebKit/Source/modules/presentation/PresentationAvailability.cpp
+++ b/third_party/WebKit/Source/modules/presentation/PresentationAvailability.cpp
@@ -18,8 +18,9 @@ namespace blink {
 namespace {
 
 WebPresentationClient* presentationClient(ExecutionContext* executionContext) {
-  ASSERT(executionContext && executionContext->isDocument());
-
+  if (!executionContext)

[dcheng, 2016/10/05 00:10:27]

Is this because we can be asked to provide a presentationClient() for a detached
context? Just curious, but how come we didn't hit this before?

[haraken, 2016/10/05 02:38:24]

You're correct.

We didn't hit this branch before because stop() had been called a bit earlier
than contextDestroyed(), which means that State::Inactive had been set a bit
earlier before.

To mitigate these kinds of subtle timing issues, I'm planning to move
notifyContextDestroyed() to the beginning of Document::shutdown() so that
contextDestroyed() is called earlier (and before Document starts any disruptive
operations).

+    return nullptr;
+  DCHECK(executionContext->isDocument());
   Document* document = toDocument(executionContext);
   if (!document->frame())
     return nullptr;
@@ -94,7 +95,7 @@ void PresentationAvailability::suspend() {
   setState(State::Suspended);
 }
 
-void PresentationAvailability::stop() {
+void PresentationAvailability::contextDestroyed() {
   setState(State::Inactive);
 }