Replace a stale fixme with a comment

Source/core/css/parser/SizesAttributeParser.cpp

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "config.h"
 #include "SizesAttributeParser.h"
 
 #include "MediaTypeNames.h"
 #include "core/css/MediaQueryEvaluator.h"
 #include "core/css/parser/MediaQueryTokenizer.h"
@@ skipping 55 matching lines @@
             if (!blockLevel)
                 break;
         }
 
         --token;
     }
 }
 
 bool SizesAttributeParser::mediaConditionMatches(PassRefPtrWillBeRawPtr<MediaQuerySet> mediaCondition)
 {
-    // FIXME: How do I handle non-screen media types here?
+    // A Media Condition cannot have a media type other then screen.

[ojan, 2014/05/16 18:21:56]

Can you make this an ASSERT instead of a comment?

[cbiesinger, 2014/05/16 18:25:44]

The comment is just explaining why the next line always passes in "screen"

     MediaQueryEvaluator mediaQueryEvaluator(MediaTypeNames::screen, *m_mediaValues);
     return mediaQueryEvaluator.eval(mediaCondition.get());
 }
 
 bool SizesAttributeParser::parseMediaConditionAndLength(MediaQueryTokenIterator startToken, MediaQueryTokenIterator endToken)
 {
     MediaQueryTokenIterator lengthTokenStart;
     MediaQueryTokenIterator lengthTokenEnd;
 
     reverseSkipIrrelevantTokens(endToken, startToken);
@@ skipping 39 matching lines @@
 }
 
 unsigned SizesAttributeParser::effectiveSizeDefaultValue()
 {
     // Returning the equivalent of "100%"
     return m_mediaValues->viewportWidth();
 }
 
 } // namespace