Generate a bit less code to handle failed arity checks.

Source/bindings/v8/custom/V8SVGLengthCustom.cpp

 /*
  * Copyright (C) 2009 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 58 matching lines @@
     ExceptionState exceptionState(info.Holder(), info.GetIsolate());
     SVGLengthContext lengthContext(wrapper->contextElement());
     imp.setValue(static_cast<float>(value->NumberValue()), lengthContext, exceptionState);
     if (exceptionState.throwIfNeeded())
         return;
     wrapper->commitChange();
 }
 
 void V8SVGLength::convertToSpecifiedUnitsMethodCustom(const v8::FunctionCallbackInfo<v8::Value>& info)
 {
+    ExceptionState exceptionState(ExceptionState::ExecutionContext, "convertToSpecifiedUnits", "SVGLength", info.Holder(), info.GetIsolate());
     SVGPropertyTearOff<SVGLength>* wrapper = V8SVGLength::toNative(info.Holder());
     if (wrapper->isReadOnly()) {
-        setDOMException(NoModificationAllowedError, info.GetIsolate());
+        exceptionState.throwDOMException(NoModificationAllowedError, "The length is read only.");
+        exceptionState.throwIfNeeded();
         return;
     }
 
     if (info.Length() < 1) {
-        throwTypeError(ExceptionMessages::failedToExecute("convertToSpecifiedUnits", "SVGLength", ExceptionMessages::notEnoughArguments(1, info.Length())), info.GetIsolate());
+        exceptionState.throwTypeError(ExceptionMessages::notEnoughArguments(1, info.Length()));
+        exceptionState.throwIfNeeded();
         return;
     }
 
     SVGLength& imp = wrapper->propertyReference();
-    ExceptionState exceptionState(info.Holder(), info.GetIsolate());
     V8TRYCATCH_VOID(int, unitType, toUInt32(info[0]));
     SVGLengthContext lengthContext(wrapper->contextElement());
     imp.convertToSpecifiedUnits(unitType, lengthContext, exceptionState);
     if (exceptionState.throwIfNeeded())
         return;
     wrapper->commitChange();
 }
 
 } // namespace WebCore