createElement should not transmit exceptions but report them.

third_party/WebKit/Source/core/dom/custom/CustomElementRegistryTest.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 "core/dom/custom/CustomElementRegistry.h"
 
 #include "bindings/core/v8/ExceptionState.h"
 #include "bindings/core/v8/ScriptValue.h"
 #include "core/dom/Document.h"
 #include "core/dom/Element.h"
@@ skipping 168 matching lines @@
   bool runConstructor(Element* element) override {
     if (constructionStack().isEmpty() || constructionStack().last() != element)
       return false;
     constructionStack().last().clear();
     return true;
   }
 
   HTMLElement* createElementSync(Document&, const QualifiedName&) override {
     return nullptr;
   }
-
-  HTMLElement* createElementSync(Document&,
-                                 const QualifiedName&,
-                                 ExceptionState&) override {
-    return nullptr;
-  }
 };
 
 // Classes which use trace macros cannot be local because of the
 // traceImpl template.
 class LogUpgradeDefinition : public TestCustomElementDefinition {
   WTF_MAKE_NONCOPYABLE(LogUpgradeDefinition);
 
  public:
   LogUpgradeDefinition(const CustomElementDescriptor& descriptor)
       : TestCustomElementDefinition(
@@ skipping 243 matching lines @@
       << "adoptedCallback should have been passed the new owner document";
 
   EXPECT_EQ(2u, definition->m_logs.size())
       << "adoptNode() should not invoke other callbacks";
 }
 
 // TODO(dominicc): Add tests which adjust the "is" attribute when type
 // extensions are implemented.
 
 }  // namespace blink