Clean forward declaration in public

public/platform/WebString.h

 /*
  * Copyright (C) 2009 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 31 matching lines @@
 #include <base/strings/nullable_string16.h>
 #include <base/strings/string16.h>
 #endif
 
 namespace WTF {
 class StringImpl;
 }
 
 namespace blink {
 
-class WebCString;
-
 // A UTF-16 string container.  It is inexpensive to copy a WebString
 // object.
 //
 // WARNING: It is not safe to pass a WebString across threads!!!
 //
 class WebString {
 public:
     ~WebString() { reset(); }
 
     WebString() { }
@@ skipping 119 matching lines @@
 }
 
 inline bool operator!=(const WebString& a, const WebString& b)
 {
     return !(a == b);
 }
 
 } // namespace blink
 
 #endif