Separate @viewport from other RuleSet construction.

third_party/WebKit/Source/core/css/parser/CSSParserImpl.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 "core/css/parser/CSSParserImpl.h"
 
 #include "core/css/CSSCustomIdentValue.h"
 #include "core/css/CSSCustomPropertyDeclaration.h"
 #include "core/css/CSSKeyframesRule.h"
 #include "core/css/CSSStyleSheet.h"
@@ skipping 596 matching lines @@
 
   if (m_observerWrapper) {
     unsigned endOffset = m_observerWrapper->endOffset(prelude);
     m_observerWrapper->observer().startRuleHeader(
         StyleRule::Viewport, m_observerWrapper->startOffset(prelude));
     m_observerWrapper->observer().endRuleHeader(endOffset);
     m_observerWrapper->observer().startRuleBody(endOffset);
     m_observerWrapper->observer().endRuleBody(endOffset);
   }
 
+  if (m_styleSheet)
+    m_styleSheet->setHasViewportRule();
+
   consumeDeclarationList(block, StyleRule::Viewport);
   return StyleRuleViewport::create(
       createStylePropertySet(m_parsedProperties, CSSViewportRuleMode));
 }
 
 StyleRuleFontFace* CSSParserImpl::consumeFontFaceRule(
     CSSParserTokenRange prelude,
     CSSParserTokenRange block) {
   if (!prelude.atEnd())
     return nullptr;  // Parse error; @font-face prelude should be empty
@@ skipping 305 matching lines @@
     else
       return nullptr;  // Parser error, invalid value in keyframe selector
     if (range.atEnd())
       return result;
     if (range.consume().type() != CommaToken)
       return nullptr;  // Parser error
   }
 }
 
 }  // namespace blink