Remove the allowfullscreen exemption for the video-specific fullscreen API (reland)

Source/core/frame/UseCounter.cpp

 /*
  * Copyright (C) 2012 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:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 904 matching lines @@
 
     case CSSSelectorPseudoShadow:
         return "::shadow pseudo-element is deprecated. See https://www.chromestatus.com/features/6750456638341120 for more details.";
 
     case PrefixedMouseEventMovementX:
         return replacedBy("webkitMovementX", "movementX");
 
     case PrefixedMouseEventMovementY:
         return replacedBy("webkitMovementY", "movementY");
 
-    case VideoFullscreenAllowedExemption:
-        return "Entering fullscreen in an <iframe> with no allowfullscreen attribute is deprecated and will stop working in M46, around October 2015. Please use the allowfullscreen attribute.";
-
     case SVGSMILElementInDocument:
     case SVGSMILAnimationInImageRegardlessOfCache:
         return "SVG's SMIL animations (<animate>, <set>, etc.) are deprecated and will be removed. Please use CSS animations or Web animations instead.";
 
     case MediaStreamLabel:
         return "'MediaStream.label' is deprecated and will be removed in M47, around November 2015. Please use 'MediaStream.id' instead.";
 
     case MediaStreamStop:
         return "'MediaStream.stop()' is deprecated and will be removed in M47, around November 2015. Please use 'MediaStream.active' instead.";
 
@@ skipping 43 matching lines @@
 UseCounter* UseCounter::getFrom(const StyleSheetContents* sheetContents)
 {
     // FIXME: We may want to handle stylesheets that have multiple owners
     //        http://crbug.com/242125
     if (sheetContents && sheetContents->hasSingleOwnerNode())
         return getFrom(sheetContents->singleOwnerDocument());
     return 0;
 }
 
 } // namespace blink