Fix "report the exception" in Custom Elements V1

third_party/WebKit/Source/bindings/core/v8/ScriptCustomElementDefinition.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 "bindings/core/v8/ScriptCustomElementDefinition.h"
 
 #include "bindings/core/v8/ScriptState.h"
 #include "bindings/core/v8/V8Binding.h"
 #include "bindings/core/v8/V8BindingMacros.h"
 #include "bindings/core/v8/V8CustomElementsRegistry.h"
@@ skipping 171 matching lines @@
 
     // 6.1.3. through 6.1.9.
     checkConstructorResult(element, document, tagName, exceptionState);
     if (exceptionState.hadException())
         return nullptr;
 
     DCHECK_EQ(element->getCustomElementState(), CustomElementState::Custom);
     return toHTMLElement(element);
 }
 
+static void dispatchErrorEvent(v8::Isolate* isolate,

[haraken, 2016/08/22 06:36:47]

origin => constructor ?

+    v8::Local<v8::Value> exception, v8::Local<v8::Object> origin)
+{
+    v8::TryCatch tryCatch(isolate);
+    tryCatch.SetVerbose(true);
+    V8ScriptRunner::throwException(isolate, exception,
+        origin.As<v8::Function>()->GetScriptOrigin());
+}
+
 HTMLElement* ScriptCustomElementDefinition::createElementSync(
     Document& document, const QualifiedName& tagName)
 {
     ScriptState::Scope scope(m_scriptState.get());
     v8::Isolate* isolate = m_scriptState->isolate();
 
     // When invoked from "create an element for a token":
     // https://html.spec.whatwg.org/multipage/syntax.html#create-an-element-for-the-token
 
     ExceptionState exceptionState(ExceptionState::ConstructionContext,
         "CustomElement", constructor(), isolate);
     HTMLElement* element = createElementSync(document, tagName, exceptionState);
 
-    if (exceptionState.hadException() || !element) {
+    if (exceptionState.hadException()) {
+        DCHECK(!element);
         // 7. If this step throws an exception, then report the exception, ...
-        {
-            v8::TryCatch tryCatch(isolate);
-            tryCatch.SetVerbose(true);
-            exceptionState.throwIfNeeded();
-        }
-
+        dispatchErrorEvent(isolate, exceptionState.getException(), constructor());
+        exceptionState.clearException();

[haraken, 2016/08/22 06:36:47]

Do you need to clear the exception here?

[kojii, 2016/08/22 06:41:33]

Not today, but when we remove throwIfNeeded()[1], it will throw but will
probably discarded (?). Since we processed it, clearing makes sense to me, but
I'm ok to remove if this doesn't look good.

[1] https://codereview.chromium.org/2061113002/

[Yuki, 2016/08/22 06:42:08]

I think we'll need to clear the exception once haraken@'s CL to remove
throwIfNeeded() gets landed.

+        // and return HTMLUnknownElement.
         return CustomElement::createFailedElement(document, tagName);
     }
+    DCHECK(element);
     return element;
 }
 
 // https://html.spec.whatwg.org/multipage/scripting.html#upgrades
 bool ScriptCustomElementDefinition::runConstructor(Element* element)
 {
     if (!m_scriptState->contextIsValid())
         return false;
     ScriptState::Scope scope(m_scriptState.get());
     v8::Isolate* isolate = m_scriptState->isolate();
 
     // Step 5 says to rethrow the exception; but there is no one to
     // catch it. The side effect is to report the error.
     v8::TryCatch tryCatch(isolate);
     tryCatch.SetVerbose(true);
 
     Element* result = runConstructor();
 
     // To report exception thrown from runConstructor()
     if (tryCatch.HasCaught())
         return false;
 
     // To report InvalidStateError Exception, when the constructor returns some different object
     if (result != element) {
         const String& message = "custom element constructors must call super() first and must "
             "not return a different object";
-        std::unique_ptr<SourceLocation> location = SourceLocation::fromFunction(constructor().As<v8::Function>());
         v8::Local<v8::Value> exception =  V8ThrowException::createDOMException(
             m_scriptState->isolate(),
             InvalidStateError,
             message);
-        fireErrorEvent(m_scriptState.get(), message, exception, std::move(location));
+        dispatchErrorEvent(isolate, exception, constructor());
         return false;
     }
 
     return true;
 }
 
 Element* ScriptCustomElementDefinition::runConstructor()
 {
     v8::Isolate* isolate = m_scriptState->isolate();
     DCHECK(ScriptState::current(isolate) == m_scriptState);
     ExecutionContext* executionContext = m_scriptState->getExecutionContext();
     v8::Local<v8::Value> result;
     if (!v8Call(V8ScriptRunner::callAsConstructor(
         isolate,
         constructor(),
         executionContext,
         0,
         nullptr),
         result)) {
         return nullptr;
     }
     return V8Element::toImplWithTypeCheck(isolate, result);
 }
 
-void ScriptCustomElementDefinition::fireErrorEvent(ScriptState* scriptState, const String& message, v8::Local<v8::Value> exception, std::unique_ptr<SourceLocation> location)
-{
-    ErrorEvent* event = ErrorEvent::create(message, std::move(location), &scriptState->world());
-    V8ErrorHandler::storeExceptionOnErrorEventWrapper(scriptState, event, exception, scriptState->context()->Global());
-    ExecutionContext* executionContext = scriptState->getExecutionContext();
-    executionContext->dispatchErrorEvent(event, NotSharableCrossOrigin);
-}
-
 v8::Local<v8::Object> ScriptCustomElementDefinition::constructor() const
 {
     DCHECK(!m_constructor.isEmpty());
     return m_constructor.newLocal(m_scriptState->isolate());
 }
 
 v8::Local<v8::Object> ScriptCustomElementDefinition::prototype() const
 {
     DCHECK(!m_prototype.isEmpty());
     return m_prototype.newLocal(m_scriptState->isolate());
@@ skipping 83 matching lines @@
         v8String(isolate, name.localName()),
         v8StringOrNull(isolate, oldValue),
         v8StringOrNull(isolate, newValue),
         v8String(isolate, name.namespaceURI()),
     };
     runCallback(m_attributeChangedCallback.newLocal(isolate), element,
         argc, argv);
 }
 
 } // namespace blink