Remove ContextLifecycleObserver from V8V0CustomElementLifecycleCallbacks

third_party/WebKit/Source/bindings/core/v8/V8V0CustomElementLifecycleCallbacks.cpp

 /*
  * Copyright (C) 2013 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 86 matching lines @@
 
 V8V0CustomElementLifecycleCallbacks::V8V0CustomElementLifecycleCallbacks(
     ScriptState* scriptState,
     v8::Local<v8::Object> prototype,
     v8::MaybeLocal<v8::Function> created,
     v8::MaybeLocal<v8::Function> attached,
     v8::MaybeLocal<v8::Function> detached,
     v8::MaybeLocal<v8::Function> attributeChanged)
     : V0CustomElementLifecycleCallbacks(
           flagSet(attached, detached, attributeChanged)),
-      ContextLifecycleObserver(scriptState->getExecutionContext()),
       m_scriptState(scriptState),
       m_prototype(scriptState->isolate(), prototype),
       m_created(scriptState->isolate(), created),
       m_attached(scriptState->isolate(), attached),
       m_detached(scriptState->isolate(), detached),
       m_attributeChanged(scriptState->isolate(), attributeChanged) {
   m_prototype.setPhantom();
 
 #define MAKE_WEAK(Var, _) \
   if (!m_##Var.isEmpty()) \
     m_##Var.setPhantom();
 
   CALLBACK_LIST(MAKE_WEAK)
 #undef MAKE_WEAK
 }
 
 V8PerContextData* V8V0CustomElementLifecycleCallbacks::creationContextData() {
-  if (!getExecutionContext())
+  if (!m_scriptState->contextIsValid())
     return 0;
 
   v8::Local<v8::Context> context = m_scriptState->context();
   if (context.IsEmpty())
     return 0;
 
   return V8PerContextData::from(context);
 }
 
 V8V0CustomElementLifecycleCallbacks::~V8V0CustomElementLifecycleCallbacks() {}
 
 bool V8V0CustomElementLifecycleCallbacks::setBinding(
     std::unique_ptr<V0CustomElementBinding> binding) {
   V8PerContextData* perContextData = creationContextData();
   if (!perContextData)
     return false;
 
   // The context is responsible for keeping the prototype
   // alive. This in turn keeps callbacks alive through hidden
   // references; see CALLBACK_LIST(SET_HIDDEN_VALUE).
   perContextData->addCustomElementBinding(std::move(binding));
   return true;
 }
 
 void V8V0CustomElementLifecycleCallbacks::created(Element* element) {
   // FIXME: callbacks while paused should be queued up for execution to
   // continue then be delivered in order rather than delivered immediately.
   // Bug 329665 tracks similar behavior for other synchronous events.
-  if (!getExecutionContext() || getExecutionContext()->isContextDestroyed())

[sof, 2016/12/07 12:14:59]

Can you clarify why the explicit checks here for isContextDestroyed() are no
longer needed?

[haraken, 2016/12/07 12:17:21]

Because it's equivalent to the m_scriptState->contextIsValid() below. Both start
returning false after the context gets detached.

[sof, 2016/12/07 12:25:14]

ok, if the interval between context() becoming null and notifyContextDestroyed()
is called, isn't observable, then this is fine.

-    return;
-
   if (!m_scriptState->contextIsValid())
     return;
 
   element->setV0CustomElementState(Element::V0Upgraded);
 
   ScriptState::Scope scope(m_scriptState.get());
   v8::Isolate* isolate = m_scriptState->isolate();
   v8::Local<v8::Context> context = m_scriptState->context();
   v8::Local<v8::Value> receiverValue =
       toV8(element, context->Global(), isolate);
   if (receiverValue.IsEmpty())
     return;
   v8::Local<v8::Object> receiver = receiverValue.As<v8::Object>();
 
   // Swizzle the prototype of the wrapper.
   v8::Local<v8::Object> prototype = m_prototype.newLocal(isolate);
   if (prototype.IsEmpty())
     return;
   if (!v8CallBoolean(receiver->SetPrototype(context, prototype)))
     return;
 
   v8::Local<v8::Function> callback = m_created.newLocal(isolate);
   if (callback.IsEmpty())
     return;
 
   v8::TryCatch exceptionCatcher(isolate);
   exceptionCatcher.SetVerbose(true);
-  V8ScriptRunner::callFunction(callback, getExecutionContext(), receiver, 0, 0,
-                               isolate);
+  V8ScriptRunner::callFunction(callback, m_scriptState->getExecutionContext(),
+                               receiver, 0, 0, isolate);
 }
 
 void V8V0CustomElementLifecycleCallbacks::attached(Element* element) {
   call(m_attached, element);
 }
 
 void V8V0CustomElementLifecycleCallbacks::detached(Element* element) {
   call(m_detached, element);
 }
 
 void V8V0CustomElementLifecycleCallbacks::attributeChanged(
     Element* element,
     const AtomicString& name,
     const AtomicString& oldValue,
     const AtomicString& newValue) {
   // FIXME: callbacks while paused should be queued up for execution to
   // continue then be delivered in order rather than delivered immediately.
   // Bug 329665 tracks similar behavior for other synchronous events.
-  if (!getExecutionContext() || getExecutionContext()->isContextDestroyed())
-    return;
-
   if (!m_scriptState->contextIsValid())
     return;
   ScriptState::Scope scope(m_scriptState.get());
   v8::Isolate* isolate = m_scriptState->isolate();
   v8::Local<v8::Context> context = m_scriptState->context();
   v8::Local<v8::Value> receiver = toV8(element, context->Global(), isolate);
   if (receiver.IsEmpty())
     return;
 
   v8::Local<v8::Function> callback = m_attributeChanged.newLocal(isolate);
   if (callback.IsEmpty())
     return;
 
   v8::Local<v8::Value> argv[] = {
       v8String(isolate, name),
       oldValue.isNull() ? v8::Local<v8::Value>(v8::Null(isolate))
                         : v8::Local<v8::Value>(v8String(isolate, oldValue)),
       newValue.isNull() ? v8::Local<v8::Value>(v8::Null(isolate))
                         : v8::Local<v8::Value>(v8String(isolate, newValue))};
 
   v8::TryCatch exceptionCatcher(isolate);
   exceptionCatcher.SetVerbose(true);
-  V8ScriptRunner::callFunction(callback, getExecutionContext(), receiver,
-                               WTF_ARRAY_LENGTH(argv), argv, isolate);
+  V8ScriptRunner::callFunction(callback, m_scriptState->getExecutionContext(),
+                               receiver, WTF_ARRAY_LENGTH(argv), argv, isolate);
 }
 
 void V8V0CustomElementLifecycleCallbacks::call(
     const ScopedPersistent<v8::Function>& weakCallback,
     Element* element) {
   // FIXME: callbacks while paused should be queued up for execution to
   // continue then be delivered in order rather than delivered immediately.
   // Bug 329665 tracks similar behavior for other synchronous events.
-  if (!getExecutionContext() || getExecutionContext()->isContextDestroyed())
-    return;
-
   if (!m_scriptState->contextIsValid())
     return;
   ScriptState::Scope scope(m_scriptState.get());
   v8::Isolate* isolate = m_scriptState->isolate();
   v8::Local<v8::Context> context = m_scriptState->context();
   v8::Local<v8::Function> callback = weakCallback.newLocal(isolate);
   if (callback.IsEmpty())
     return;
 
   v8::Local<v8::Value> receiver = toV8(element, context->Global(), isolate);
   if (receiver.IsEmpty())
     return;
 
   v8::TryCatch exceptionCatcher(isolate);
   exceptionCatcher.SetVerbose(true);
-  V8ScriptRunner::callFunction(callback, getExecutionContext(), receiver, 0, 0,
-                               isolate);
+  V8ScriptRunner::callFunction(callback, m_scriptState->getExecutionContext(),
+                               receiver, 0, 0, isolate);
 }
 
 DEFINE_TRACE(V8V0CustomElementLifecycleCallbacks) {
   V0CustomElementLifecycleCallbacks::trace(visitor);
-  ContextLifecycleObserver::trace(visitor);
 }
 
 }  // namespace blink