Implement minlength for <input> and <textarea>.

Source/core/html/HTMLInputElement.h

Index: Source/core/html/HTMLInputElement.h
diff --git a/Source/core/html/HTMLInputElement.h b/Source/core/html/HTMLInputElement.h
index c17851961ba46825cd7308057683992336de8f01..80b47ccb75c4416f28a312e2400026a276dcdbcf 100644
--- a/Source/core/html/HTMLInputElement.h
+++ b/Source/core/html/HTMLInputElement.h
@@ -62,6 +62,7 @@ public:
     virtual bool rangeOverflow() const OVERRIDE FINAL;
     virtual bool stepMismatch() const OVERRIDE FINAL;
     virtual bool tooLong() const OVERRIDE FINAL;
+    virtual bool tooShort() const OVERRIDE FINAL;
     virtual bool typeMismatch() const OVERRIDE FINAL;
     virtual bool valueMissing() const OVERRIDE FINAL;
     virtual String validationMessage() const OVERRIDE FINAL;
@@ -169,7 +170,9 @@ public:
     KURL src() const;
 
     int maxLength() const;
+    int minLength() const;
     void setMaxLength(int, ExceptionState&);
+    void setMinLength(int, ExceptionState&);
 
     bool multiple() const;
 
@@ -316,6 +319,7 @@ private:
     virtual bool isOutOfRange() const OVERRIDE FINAL;
 
     bool tooLong(const String&, NeedsToCheckDirtyFlag) const;
+    bool tooShort(const String&, NeedsToCheckDirtyFlag) const;
 
     virtual bool supportsPlaceholder() const OVERRIDE FINAL;
     virtual void updatePlaceholderText() OVERRIDE FINAL;
@@ -337,6 +341,7 @@ private:
     void setListAttributeTargetObserver(PassOwnPtrWillBeRawPtr<ListAttributeTargetObserver>);
     void resetListAttributeTargetObserver();
     void parseMaxLengthAttribute(const AtomicString&);
+    void parseMinLengthAttribute(const AtomicString&);
     void updateValueIfNeeded();
 
     // Returns null if this isn't associated with any radio button group.
@@ -354,6 +359,7 @@ private:
     String m_suggestedValue;
     int m_size;
     int m_maxLength;
+    int m_minLength;
     short m_maxResults;
     bool m_isChecked : 1;
     bool m_reflectsCheckedAttribute : 1;