Split WebLocalFrame into a distinct subclass of WebFrame.

Source/web/mac/WebSubstringUtil.mm

 /*
  * Copyright (C) 2005, 2007, 2008 Apple Inc. All rights reserved.
  * Copyright (C) 2011 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.
@@ skipping 129 matching lines @@
         NSDictionary* attributes = [string attributesAtIndex:0 effectiveRange:NULL];
         NSFont* font = [attributes objectForKey:NSFontAttributeName];
         if (font)
             stringPoint.move(0, ceil(-[font descender]));
     }
 
     baselinePoint = stringPoint;
     return string;
 }
 
-NSAttributedString* WebSubstringUtil::attributedSubstringInRange(WebFrame* webFrame, size_t location, size_t length)
+NSAttributedString* WebSubstringUtil::attributedSubstringInRange(WebLocalFrame* webFrame, size_t location, size_t length)
 {
     LocalFrame* frame = toWebFrameImpl(webFrame)->frame();
     if (frame->view()->needsLayout())
         frame->view()->layout();
 
     Element* editable = frame->selection().rootEditableElementOrDocumentElement();
     ASSERT(editable);
     RefPtrWillBeRawPtr<Range> range(PlainTextRange(location, location + length).createRange(*editable));
     if (!range)
         return nil;
 
     return attributedSubstringFromRange(range.get());
 }
 
 } // namespace blink