Derive the step base for an input element as (now) specified.

Source/core/html/forms/InputType.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2001 Dirk Mueller (mueller@kde.org)
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011 Apple Inc. All rights reserved.
  *           (C) 2006 Alexey Proskuryakov (ap@nypop.com)
  * Copyright (C) 2007 Samuel Weinig (sam@webkit.org)
  * Copyright (C) 2009, 2010, 2011, 2012 Google Inc. All rights reserved.
  * Copyright (C) 2012 Samsung Electronics. All rights reserved.
  *
@@ skipping 967 matching lines @@
 }
 
 void InputType::countUsageIfVisible(UseCounter::Feature feature) const
 {
     if (RenderStyle* style = element().renderStyle()) {
         if (style->visibility() != HIDDEN)
             UseCounter::count(element().document(), feature);
     }
 }
 
+Decimal InputType::findStepBase(const Decimal& defaultValue) const

[yosin_UTC9, 2013/11/27 01:28:05]

The word "find" leads me the function has loop. How about "calculateStepBase()"
or better?

+{
+    Decimal stepBase = parseToNumber(element().fastGetAttribute(minAttr), Decimal::nan());

[yosin_UTC9, 2013/11/27 01:28:05]

nit: const Decimal stepBase = ...;

+    if (!stepBase.isFinite())
+        stepBase = parseToNumber(element().fastGetAttribute(valueAttr), defaultValue);

[yosin_UTC9, 2013/11/27 01:28:05]

nit: rather than copying, just |return parseToNumber(...);|

+    return stepBase;
+}
+
 } // namespace WebCore