createElement should not transmit exceptions but report them.

third_party/WebKit/Source/core/dom/custom/CustomElementTestHelpers.h

Index: third_party/WebKit/Source/core/dom/custom/CustomElementTestHelpers.h
diff --git a/third_party/WebKit/Source/core/dom/custom/CustomElementTestHelpers.h b/third_party/WebKit/Source/core/dom/custom/CustomElementTestHelpers.h
index 813413d6f3c6eaec2c84ba4e1bafba013d3e57a1..9fde0738214c910ba6a811d13c3884ebfbe3fb42 100644
--- a/third_party/WebKit/Source/core/dom/custom/CustomElementTestHelpers.h
+++ b/third_party/WebKit/Source/core/dom/custom/CustomElementTestHelpers.h
@@ -65,12 +65,6 @@ class TestCustomElementDefinition : public CustomElementDefinition {
     return createElementForConstructor(document);
   }
 
-  HTMLElement* createElementSync(Document& document,
-                                 const QualifiedName&,
-                                 ExceptionState&) override {
-    return createElementForConstructor(document);
-  }
-
   bool hasConnectedCallback() const override { return false; }
   bool hasDisconnectedCallback() const override { return false; }
   bool hasAdoptedCallback() const override { return false; }