Split custom element script use and move it into bindings

third_party/WebKit/Source/bindings/core/v8/ScriptCustomElementDefinitionBuilder.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/ScriptCustomElementDefinitionBuilder.h"
+
+#include "bindings/core/v8/DOMWrapperWorld.h"
+#include "bindings/core/v8/ExceptionState.h"
+#include "bindings/core/v8/ScriptCustomElementDefinition.h"
+#include "bindings/core/v8/ScriptState.h"
+#include "bindings/core/v8/ScriptValue.h"
+#include "bindings/core/v8/V8Binding.h"
+#include "bindings/core/v8/V8BindingMacros.h"
+#include "core/dom/ExceptionCode.h"
+
+namespace blink {
+
+ScriptCustomElementDefinitionBuilder::ScriptCustomElementDefinitionBuilder(
+    ScriptState* scriptState,
+    CustomElementsRegistry* registry,
+    const ScriptValue& constructor,
+    ExceptionState& exceptionState)
+    : m_scriptState(scriptState)
+    , m_registry(registry)
+    , m_constructorValue(constructor.v8Value())
+    , m_exceptionState(exceptionState)
+{
+}
+
+void ScriptCustomElementDefinitionBuilder::checkConstructorIntrinsics()
+{
+    DCHECK(m_scriptState->world().isMainWorld());
+
+    if (!m_constructorValue->IsFunction()) {
+        // Not even a function.
+        m_exceptionState.throwTypeError(
+            "constructor argument is not a constructor");
+        return;
+    }
+    m_constructor = m_constructorValue.As<v8::Object>();
+    if (!m_constructor->IsConstructor()) {
+        m_exceptionState.throwTypeError(
+            "constructor argument is not a constructor");
+        return;
+    }
+}
+
+void ScriptCustomElementDefinitionBuilder::checkConstructorNotRegistered()
+{
+    if (ScriptCustomElementDefinition::forConstructor(
+        m_scriptState,
+        m_registry,
+        m_constructor)) {
+
+        // Constructor is already registered.
+        m_exceptionState.throwDOMException(
+            NotSupportedError,
+            "this constructor has already been used with this registry");
+    }
+}
+
+bool ScriptCustomElementDefinitionBuilder::checkPrototype()
+{
+    v8::Isolate* isolate = m_scriptState->isolate();
+    v8::Local<v8::Context> context = m_scriptState->context();
+    v8::TryCatch tryCatch(isolate);

[haraken, 2016/05/26 08:33:46]

I think you can remove TryCatch. Checking the return value of v8Call would be
enough.

[dominicc (has gone to gerrit), 2016/05/27 04:54:17]

Done.

+    v8::Local<v8::String> prototypeString =
+        v8AtomicString(isolate, "prototype");
+    v8::Local<v8::Value> prototypeValue;
+    if (!v8Call(
+        m_constructor->Get(context, prototypeString), prototypeValue)) {
+        DCHECK(tryCatch.HasCaught());
+        tryCatch.ReThrow();
+        return false;
+    }
+    if (!prototypeValue->IsObject()) {
+        DCHECK(!tryCatch.HasCaught());
+        m_exceptionState.throwTypeError(
+            "constructor prototype is not an object");
+        return false;
+    }
+    m_prototype = prototypeValue.As<v8::Object>();
+    return m_scriptState->contextIsValid();

[haraken, 2016/05/26 08:33:46]

What is this checking?

[dominicc (has gone to gerrit), 2016/05/27 04:54:17]

Retrieving the prototype can run script and detach the window. See
third_party/WebKit/LayoutTests/custom-elements/define-context-dies-retrieving-prototype.html

+}
+
+CustomElementDefinition* ScriptCustomElementDefinitionBuilder::build(
+    const CustomElementDescriptor& descriptor)
+{
+    return ScriptCustomElementDefinition::create(
+        m_scriptState,
+        m_registry,
+        descriptor,
+        m_constructor,
+        m_prototype);
+}
+
+} // namespace blink