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

third_party/WebKit/Source/core/css/resolver/SharedStyleFinderTest.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/css/resolver/SharedStyleFinder.h"
 
 #include "core/css/RuleFeature.h"
 #include "core/css/RuleSet.h"
 #include "core/css/parser/CSSParser.h"
+#include "core/css/parser/CSSParserContext.h"
 #include "core/dom/Document.h"
 #include "core/frame/FrameView.h"
 #include "core/html/HTMLElement.h"
 #include "core/testing/DummyPageHolder.h"
 #include "testing/gtest/include/gtest/gtest.h"
 #include <memory>
 
 namespace blink {
 
 class SharedStyleFinderTest : public ::testing::Test {
@@ skipping 155 matching lines @@
   ASSERT_TRUE(b);
 
   EXPECT_FALSE(a->isDragged());
   EXPECT_FALSE(b->isDragged());
 
   EXPECT_TRUE(matchesUncommonAttributeRuleSet(*a));
   EXPECT_FALSE(matchesUncommonAttributeRuleSet(*b));
 }
 
 }  // namespace blink