Deprecate the allowfullscreen exemption for <video>

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 899 matching lines @@
 
     case PrefixedTouchForce:
         return "'Touch.webkitForce' is deprecated and will be removed in M47, around November 2015. Please use 'Touch.force' instead.";
 
     case CSSDeepCombinator:
         return "/deep/ combinator is deprecated. See https://www.chromestatus.com/features/6750456638341120 for more details.";
 
     case CSSSelectorPseudoShadow:
         return "::shadow pseudo-element is deprecated. See https://www.chromestatus.com/features/6750456638341120 for more details.";
 
+    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.";

[falken, 2015/06/08 03:22:29]

Hum, I don't know whether Blink should refer to Chrome milestones, since there
can be other embedders. But I see other strings here do it too.

[philipj_slow, 2015/06/09 19:17:17]

Yeah, this looks a bit odd, but Chromium is the only Blink embedder and there's
no other human-understandable version number we could really use here.

+
     // Features that aren't deprecated don't have a deprecation message.
     default:
         return String();
     }
 }
 
 void UseCounter::count(CSSParserContext context, CSSPropertyID feature)
 {
     ASSERT(feature >= firstCSSProperty);
     ASSERT(feature <= lastUnresolvedCSSProperty);
@@ skipping 27 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