Dispatching errors across iframes don't match webplatform tests

third_party/WebKit/Source/bindings/core/v8/V8Initializer.cpp

Index: third_party/WebKit/Source/bindings/core/v8/V8Initializer.cpp
diff --git a/third_party/WebKit/Source/bindings/core/v8/V8Initializer.cpp b/third_party/WebKit/Source/bindings/core/v8/V8Initializer.cpp
index 511642a838a24ce41f442df29f764fa13a5f3f69..0a633559d9f00c1d39acb53c21107ae4c9141459 100644
--- a/third_party/WebKit/Source/bindings/core/v8/V8Initializer.cpp
+++ b/third_party/WebKit/Source/bindings/core/v8/V8Initializer.cpp
@@ -145,9 +145,18 @@ static void messageHandlerInMainThread(v8::Local<v8::Message> message,
   else if (message->IsSharedCrossOrigin())
     accessControlStatus = SharableCrossOrigin;
 
+  ScriptState* errorEventScriptState = context->errorEventScriptState();

[haraken, 2016/10/15 02:25:25]

Add a comment about what this is doing.

[dominicc (has gone to gerrit), 2016/10/16 08:45:57]

This could be simpler if the errorEventScriptState always returns a script
state--one for the context if one was not explicitly set.

It may make sense to use context and not script state here since that's lighter.
haraken WDYT?

+  if (!errorEventScriptState)
+      errorEventScriptState = scriptState;
+
+  if (!errorEventScriptState->contextIsValid())
+      return;
+
+  ExecutionContext* errorEventContext =
+      errorEventScriptState->getExecutionContext();
   ErrorEvent* event =
       ErrorEvent::create(toCoreStringWithNullCheck(message->Get()),
-                         std::move(location), &scriptState->world());
+                         std::move(location), &errorEventScriptState->world());
 
   String messageForConsole = extractMessageForConsole(isolate, data);
   if (!messageForConsole.isEmpty())
@@ -158,15 +167,15 @@ static void messageHandlerInMainThread(v8::Local<v8::Message> message,
   // during context creation.
   // FIXME: Can we even get here during initialization now that we bail out when
   // GetEntered returns an empty handle?
-  if (context->isDocument()) {
-    LocalFrame* frame = toDocument(context)->frame();
-    if (frame && frame->script().existingWindowProxy(scriptState->world())) {
+  if (errorEventContext->isDocument()) {
+    LocalFrame* frame = toDocument(errorEventContext)->frame();
+    if (frame && frame->script().existingWindowProxy(errorEventScriptState->world())) {
       V8ErrorHandler::storeExceptionOnErrorEventWrapper(
-          scriptState, event, data, scriptState->context()->Global());
+          errorEventScriptState, event, data, errorEventScriptState->context()->Global());
     }
   }
 
-  if (scriptState->world().isPrivateScriptIsolatedWorld()) {
+  if (errorEventScriptState->world().isPrivateScriptIsolatedWorld()) {
     // We allow a private script to dispatch error events even in a
     // EventDispatchForbiddenScope scope.  Without having this ability, it's
     // hard to debug the private script because syntax errors in the private
@@ -175,9 +184,9 @@ static void messageHandlerInMainThread(v8::Local<v8::Message> message,
     // error events don't propagate to other isolated worlds (which means that
     // the error events won't fire any event listeners in user's scripts).
     EventDispatchForbiddenScope::AllowUserAgentEvents allowUserAgentEvents;
-    context->dispatchErrorEvent(event, accessControlStatus);
+    errorEventContext->dispatchErrorEvent(event, accessControlStatus);
   } else {
-    context->dispatchErrorEvent(event, accessControlStatus);
+    errorEventContext->dispatchErrorEvent(event, accessControlStatus);
   }
 }