Split the CSSParserContext class out of CSSParserMode into its own file.

third_party/WebKit/Source/core/dom/SelectorQueryTest.cpp

 // Copyright 2016 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/dom/SelectorQuery.h"
 
 #include "core/css/parser/CSSParser.h"
+#include "core/css/parser/CSSParserContext.h"
 #include "core/dom/Document.h"
 #include "core/html/HTMLDocument.h"
 #include "core/html/HTMLHtmlElement.h"
 #include "testing/gtest/include/gtest/gtest.h"
 #include <memory>
 
 namespace blink {
 
 TEST(SelectorQueryTest, NotMatchingPseudoElement) {
   Document* document = Document::create();
@@ skipping 34 matching lines @@
                        CSSParserContext::StaticProfile),
       nullptr, "p:last-of-type");
   std::unique_ptr<SelectorQuery> query =
       SelectorQuery::adopt(std::move(selectorList));
   Element* elm = query->queryFirst(*document);
   ASSERT_TRUE(elm);
   EXPECT_EQ("last", elm->idForStyleResolution());
 }
 
 }  // namespace blink