Remove unused HTMLTextFormControlElement::maxLength.

No one calls maxLength for HTMLTextFormControlElement though
HTMLInputElement::maxLength and HTMLTextAreaElement::maxLength are used. We can
remove HTMLTextFormControlElement::maxLength, and stop overriding it in
HTMLInputElement and HTMLTextAreaElement.

BUG=none
TEST=none; no behavior changes.

Review URL: https://codereview.chromium.org/137783010

git-svn-id: svn://svn.chromium.org/blink/trunk@165129 bbb929c8-8fbe-4397-9dbb-9b2b20218538

third_party/WebKit/Source/core/html/HTMLInputElement.h

@@ -198,7 +198,7 @@ public:
 
     KURL src() const;
 
-    virtual int maxLength() const OVERRIDE FINAL;
+    int maxLength() const;
     void setMaxLength(int, ExceptionState&);
 
     bool multiple() const;

third_party/WebKit/Source/core/html/HTMLTextAreaElement.h

@@ -46,7 +46,7 @@ public:
     String defaultValue() const;
     void setDefaultValue(const String&);
     int textLength() const { return value().length(); }
-    virtual int maxLength() const OVERRIDE;
+    int maxLength() const;
     void setMaxLength(int, ExceptionState&);
 
     String suggestedValue() const;

third_party/WebKit/Source/core/html/HTMLTextFormControlElement.h

@@ -73,7 +73,6 @@ public:
 
     virtual void dispatchFormControlChangeEvent() OVERRIDE FINAL;
 
-    virtual int maxLength() const = 0;
     virtual String value() const = 0;
 
     HTMLElement* innerTextElement() const;