Add support for 'display-mode' MQ defined in Manifest spec

Source/core/css/MediaValuesDynamic.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 "core/css/MediaValuesDynamic.h"
 
 #include "core/css/CSSHelper.h"
 #include "core/css/CSSPrimitiveValue.h"
 #include "core/css/CSSToLengthConversionData.h"
@@ skipping 109 matching lines @@
 bool MediaValuesDynamic::threeDEnabled() const
 {
     return calculateThreeDEnabled(m_frame);
 }
 
 const String MediaValuesDynamic::mediaType() const
 {
     return calculateMediaType(m_frame);
 }
 
+DisplayMode MediaValuesDynamic::displayMode() const
+{
+    return calculateDisplayMode(m_frame);
+}
+
 bool MediaValuesDynamic::strictMode() const
 {
     return calculateStrictMode(m_frame);
 }
 
 Document* MediaValuesDynamic::document() const
 {
     return m_frame->document();
 }
 
 bool MediaValuesDynamic::hasValues() const
 {
     return m_frame;
 }
 
 } // namespace