Implement minlength for <input> and <textarea>.

Source/core/html/HTMLTextAreaElement.h

Index: Source/core/html/HTMLTextAreaElement.h
diff --git a/Source/core/html/HTMLTextAreaElement.h b/Source/core/html/HTMLTextAreaElement.h
index b5f9ffb4b5f7320263d27d014696545f513cf86c..171081d458d165df485c4087cf13458175b98ce7 100644
--- a/Source/core/html/HTMLTextAreaElement.h
+++ b/Source/core/html/HTMLTextAreaElement.h
@@ -47,7 +47,9 @@ public:
     void setDefaultValue(const String&);
     int textLength() const { return value().length(); }
     int maxLength() const;
+    int minLength() const;
     void setMaxLength(int, ExceptionState&);
+    void setMinLength(int, ExceptionState&);
 
     String suggestedValue() const;
     void setSuggestedValue(const String&);
@@ -56,6 +58,7 @@ public:
     virtual String validationMessage() const OVERRIDE;
     virtual bool valueMissing() const OVERRIDE;
     virtual bool tooLong() const OVERRIDE;
+    virtual bool tooShort() const OVERRIDE;
     bool isValidValue(const String&) const;
 
     void setCols(int);
@@ -122,6 +125,7 @@ private:
 
     bool valueMissing(const String& value) const { return isRequiredFormControl() && !isDisabledOrReadOnly() && value.isEmpty(); }
     bool tooLong(const String&, NeedsToCheckDirtyFlag) const;
+    bool tooShort(const String&, NeedsToCheckDirtyFlag) const;
 
     int m_rows;
     int m_cols;