Implement minlength for <input> and <textarea>.

Source/core/html/forms/InputType.cpp

Index: Source/core/html/forms/InputType.cpp
diff --git a/Source/core/html/forms/InputType.cpp b/Source/core/html/forms/InputType.cpp
index 27d69d87471e9b92722ef3773c1e1286a022f858..1da08da15942c3c79ef7482c2af50cf136b5cd88 100644
--- a/Source/core/html/forms/InputType.cpp
+++ b/Source/core/html/forms/InputType.cpp
@@ -239,6 +239,11 @@ bool InputType::tooLong(const String&, HTMLTextFormControlElement::NeedsToCheckD
     return false;
 }
 
+bool InputType::tooShort(const String&, HTMLTextFormControlElement::NeedsToCheckDirtyFlag) const
+{
+    return false;
+}
+
 bool InputType::patternMismatch(const String&) const
 {
     return false;
@@ -370,6 +375,9 @@ String InputType::validationMessage() const
     if (element().tooLong())
         return locale().validationMessageTooLongText(value.length(), element().maxLength());
 
+    if (element().tooShort())
+        return locale().validationMessageTooShortText(value.length(), element().minLength());
+
     if (!isSteppable())
         return emptyString();
 
@@ -650,6 +658,11 @@ int InputType::maxLength() const
     return HTMLInputElement::maximumLength;
 }
 
+int InputType::minLength() const
+{
+    return 0;
+}
+
 bool InputType::supportsPlaceholder() const
 {
     return false;