Merge 97351 - REGRESSION(r89915): <input type=email multiple> don't show the default value

Source/WebCore/html/HTMLInputElement.cpp

Index: Source/WebCore/html/HTMLInputElement.cpp
===================================================================
--- Source/WebCore/html/HTMLInputElement.cpp	(revision 97687)
+++ Source/WebCore/html/HTMLInputElement.cpp	(working copy)
@@ -1414,6 +1414,8 @@
 
 String HTMLInputElement::sanitizeValue(const String& proposedValue) const
 {
+    if (proposedValue.isNull())
+        return proposedValue;
     return m_inputType->sanitizeValue(proposedValue);
 }
 
@@ -1955,6 +1957,7 @@
 void HTMLInputElement::updateValueIfNeeded()
 {
     String newValue = sanitizeValue(m_valueIfDirty);
+    ASSERT(!m_valueIfDirty.isNull() || newValue.isNull());
     if (newValue != m_valueIfDirty)
         setValue(newValue);
 }