input[type=range]: Updating step attribute should align the value to steps.

third_party/WebKit/Source/core/html/forms/RangeInputType.cpp

Index: third_party/WebKit/Source/core/html/forms/RangeInputType.cpp
diff --git a/third_party/WebKit/Source/core/html/forms/RangeInputType.cpp b/third_party/WebKit/Source/core/html/forms/RangeInputType.cpp
index 5b1a738b12174e013a14a408c35f2ab128ad1bcb..99c65ab40b788f5ff1ac69c738173b12de8475a0 100644
--- a/third_party/WebKit/Source/core/html/forms/RangeInputType.cpp
+++ b/third_party/WebKit/Source/core/html/forms/RangeInputType.cpp
@@ -273,6 +273,13 @@ void RangeInputType::sanitizeValueInResponseToMinOrMaxAttributeChange()
     element().updateView();
 }
 
+void RangeInputType::stepAttributeChanged()
+{
+    if (element().hasDirtyValue())
+        element().setValue(element().value());
+    element().updateView();
+}
+
 void RangeInputType::setValue(const String& value, bool valueChanged, TextFieldEventBehavior eventBehavior)
 {
     InputType::setValue(value, valueChanged, eventBehavior);