Fix switching interceptor if element needs to upgraded after custom element is registered

Source/bindings/core/dart/DartJsInterop.cpp

Index: Source/bindings/core/dart/DartJsInterop.cpp
diff --git a/Source/bindings/core/dart/DartJsInterop.cpp b/Source/bindings/core/dart/DartJsInterop.cpp
index 7d6498dc64925223ce02e25b1cf395316bb3d055..5f4037cd4397f7dcbd7f1dd34cae3c3784ba6803 100644
--- a/Source/bindings/core/dart/DartJsInterop.cpp
+++ b/Source/bindings/core/dart/DartJsInterop.cpp
@@ -1697,6 +1697,67 @@ fail:
     ASSERT_NOT_REACHED();
 }
 
+// Callback to force an instance to adopt a a specific custom element type.
+// Element accessed before custom class registerElement called.  After which
+// each element with 'is' attribute custom type createdCallback is called with
+// the element to upgrade.
+static void setInstanceInterceptorCustomUpgradeCallback(Dart_NativeArguments args)
+{
+    Dart_Handle exception = 0;
+    {
+        DartDOMData* domData = static_cast<DartDOMData*>(Dart_GetNativeIsolateData(args));
+        auto v8Isolate = domData->v8Isolate();
+        v8::Local<v8::Context> context = domData->v8Context();
+        JsInteropScopes scopes(args, context);
+        JsObject* jsObject = toJsObject(args, 0, exception);
+        if (exception)
+            goto fail;
+        v8::Local<v8::Object> v8Object = jsObject->localV8Object(v8Isolate);
+        if (scopes.handleJsException(&exception))
+            goto fail;
+
+        // Get the type of the element (check to see if the interceptor is the
+        // CustomElementType).
+        Dart_Handle arg0 = Dart_GetNativeArgument(args, 0);
+        Dart_Handle dartType = Dart_InstanceGetType(arg0);
+        ASSERT(Dart_IsType(dartType));
+        ASSERT(!Dart_IsError(dartType));
+        Dart_Handle instanceType = Dart_TypeName(dartType);
+
+        // Get the interceptor
+        auto cache = domData->m_dartHandles.get(v8Object, v8Isolate);
+        InterceptorData* interceptor = jsObject->computeInterceptor(v8Object, domData, cache);
+
+        // Get the interceptor's custom element type.
+        Dart_Handle interceptorType = Dart_HandleFromPersistent(interceptor->m_type);
+        ASSERT(Dart_IsType(interceptorType));
+        ASSERT(!Dart_IsError(interceptorType));
+        Dart_Handle customType = Dart_TypeName(interceptorType);
+        ASSERT(Dart_IsType(customType));
+        ASSERT(!Dart_IsError(customType));

[Jacob, 2016/04/22 16:46:16]

no need to have both the IsType and not IsError asserts.

[terry, 2016/04/22 18:48:29]

Yep, eliminated Dart_IsError.

+
+        bool equal;

[Jacob, 2016/04/22 16:46:16]

For safety change to
bool equal = false;
as you aren't checking whether Dart_ObjectEquals blows up.

[terry, 2016/04/22 18:48:29]

Done.

+        Dart_ObjectEquals(instanceType, customType, &equal);
+        if (!equal) {
+          // Type of the instance isn't the same as the custom element type so
+          // then we must change the interceptor.  Upgrade to the registered
+          // element.
+          RELEASE_ASSERT(interceptor->m_isCustomElement);
+          cache->m_typedInterop = 0; // Clear existing handle.
+          scopes.setReturnValue(JsObject::createTyped(v8Object, domData, interceptor, cache));
+
+          if (scopes.handleJsException(&exception))
+            goto fail;
+        }
+        return;
+    }
+
+fail:
+    Dart_ThrowException(exception);
+    ASSERT_NOT_REACHED();
+}
+
+
 static void callMethodCallbackHelper(Dart_NativeArguments args, bool legacy)
 {
     Dart_Handle exception = 0;
@@ -2386,6 +2447,7 @@ static DartNativeEntry nativeEntries[] = {
     { JsInteropInternal::defineInterceptorCustomElementCallback, 2, "Utils_defineInterceptorCustomElement" },
     { JsInteropInternal::defineInterceptorCallback, 2, "Utils_defineInterceptor" },
     { JsInteropInternal::setInstanceInterceptorCallback, 3, "Utils_setInstanceInterceptor" },
+    { JsInteropInternal::setInstanceInterceptorCustomUpgradeCallback, 1, "Utils_setInstanceInterceptorCustomUpgrade" },
     { JsInteropInternal::initializeCustomElement, 1, "Utils_initializeCustomElement" },
 
     { JsInteropInternal::toTypedObjectCallback, 1, "JSNative_toTypedObject" },