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

Source/core/html/forms/NumberInputType.cpp

 /*
  * Copyright (C) 2010 Google Inc. All rights reserved.
  * Copyright (C) 2011 Apple 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.
@@ skipping 147 matching lines @@
 
 bool NumberInputType::typeMismatch() const
 {
     ASSERT(!typeMismatchFor(element().value()));
     return false;
 }
 
 StepRange NumberInputType::createStepRange(AnyStepHandling anyStepHandling) const
 {
     DEFINE_STATIC_LOCAL(const StepRange::StepDescription, stepDescription, (numberDefaultStep, numberDefaultStepBase, numberStepScaleFactor));
-    const Decimal stepBase = parseToDecimalForNumberType(element().fastGetAttribute(minAttr), numberDefaultStepBase);
+
+    const Decimal stepBase = parseToNumber(element().fastGetAttribute(minAttr), element().fastGetAttribute(valueAttr), numberDefaultStepBase);
     // FIXME: We should use numeric_limits<double>::max for number input type.
     const Decimal floatMax = Decimal::fromDouble(numeric_limits<float>::max());
-    const Decimal minimum = parseToNumber(element().fastGetAttribute(minAttr), -floatMax);
-    const Decimal maximum = parseToNumber(element().fastGetAttribute(maxAttr), floatMax);
+    const Decimal minimum = parseToNumber(element().fastGetAttribute(minAttr), String(), -floatMax);
+    const Decimal maximum = parseToNumber(element().fastGetAttribute(maxAttr), String(), floatMax);
     const Decimal step = StepRange::parseStep(anyStepHandling, stepDescription, element().fastGetAttribute(stepAttr));
     return StepRange(stepBase, minimum, maximum, step, stepDescription);
 }
 
 bool NumberInputType::sizeShouldIncludeDecoration(int defaultSize, int& preferredSize) const
 {
     preferredSize = defaultSize;
 
     const String stepString = element().fastGetAttribute(stepAttr);
     if (equalIgnoringCase(stepString, "any"))
@@ skipping 22 matching lines @@
     return true;
 }
 
 void NumberInputType::handleKeydownEvent(KeyboardEvent* event)
 {
     handleKeydownEventForSpinButton(event);
     if (!event->defaultHandled())
         TextFieldInputType::handleKeydownEvent(event);
 }
 
-Decimal NumberInputType::parseToNumber(const String& src, const Decimal& defaultValue) const
+Decimal NumberInputType::parseToNumber(const String& src, const String& alternative, const Decimal& defaultValue) const
 {
+    if (!alternative.isEmpty()) {
+        Decimal result = parseToDecimalForNumberType(src, Decimal::nan());
+        if (!result.isFinite())
+            result = parseToDecimalForNumberType(alternative, defaultValue);
+
+        return result;
+    }
     return parseToDecimalForNumberType(src, defaultValue);
 }
 
 String NumberInputType::serialize(const Decimal& value) const
 {
     if (!value.isFinite())
         return String();
     return serializeForNumberType(value);
 }
 
@@ skipping 80 matching lines @@
 
 void NumberInputType::stepAttributeChanged()
 {
     InputType::stepAttributeChanged();
 
     if (element().renderer())
         element().renderer()->setNeedsLayoutAndPrefWidthsRecalc();
 }
 
 } // namespace WebCore