Added a UseCounter for hover:on-demand media query parsing.

third_party/WebKit/Source/core/css/MediaQueryEvaluator.cpp

 /*
  * CSS Media Query Evaluator
  *
  * Copyright (C) 2006 Kimmo Kinnunen <kimmo.t.kinnunen@nokia.com>.
  * Copyright (C) 2013 Apple Inc. All rights reserved.
  * Copyright (C) 2013 Intel Corporation. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
@@ skipping 626 matching lines @@
                                   MediaFeaturePrefix,
                                   const MediaValues& mediaValues) {
   HoverType hover = mediaValues.primaryHoverType();
 
   if (!value.isValid())
     return hover != HoverTypeNone;
 
   if (!value.isID)
     return false;
 
+  if (value.id == CSSValueOnDemand)
+    UseCounter::count(mediaValues.document(), UseCounter::CSSValueOnDemand);
+
   return (hover == HoverTypeNone && value.id == CSSValueNone) ||
          (hover == HoverTypeOnDemand && value.id == CSSValueOnDemand) ||
          (hover == HoverTypeHover && value.id == CSSValueHover);
 }
 
 static bool anyHoverMediaFeatureEval(const MediaQueryExpValue& value,
                                      MediaFeaturePrefix,
                                      const MediaValues& mediaValues) {
   int availableHoverTypes = mediaValues.availableHoverTypes();
 
   if (!value.isValid())
     return availableHoverTypes & ~HoverTypeNone;
 
   if (!value.isID)
     return false;
 
   switch (value.id) {
     case CSSValueNone:
       return availableHoverTypes & HoverTypeNone;
     case CSSValueOnDemand:
+      UseCounter::count(mediaValues.document(), UseCounter::CSSValueOnDemand);
       return availableHoverTypes & HoverTypeOnDemand;
     case CSSValueHover:
       return availableHoverTypes & HoverTypeHover;
     default:
       ASSERT_NOT_REACHED();
       return false;
   }
 }
 
 static bool pointerMediaFeatureEval(const MediaQueryExpValue& value,
@@ skipping 137 matching lines @@
   // Call the media feature evaluation function. Assume no prefix and let
   // trampoline functions override the prefix if prefix is used.
   EvalFunc func = gFunctionMap->get(expr->mediaFeature().impl());
   if (func)
     return func(expr->expValue(), NoPrefix, *m_mediaValues);
 
   return false;
 }
 
 }  // namespace blink