Remove unused headers from CSSPropertyParser.cpp

Bug: 668012
Change-Id: Ib461879750e52584990e1547c3807b12e08d6972
Reviewed-on: https://chromium-review.googlesource.com/663103Reviewed-by: nainar <nainar@chromium.org>
Commit-Queue: Bugs Nash <bugsnash@chromium.org>
Cr-Commit-Position: refs/heads/master@{#501499}

third_party/WebKit/Source/core/css/parser/CSSPropertyParser.cpp

@@ -4,35 +4,27 @@
 
 #include "core/css/parser/CSSPropertyParser.h"
 
-#include <memory>
 #include "core/StylePropertyShorthand.h"
 #include "core/css/CSSFontFaceSrcValue.h"
-#include "core/css/CSSIdentifierValue.h"
 #include "core/css/CSSInheritedValue.h"
 #include "core/css/CSSInitialValue.h"
 #include "core/css/CSSPendingSubstitutionValue.h"
-#include "core/css/CSSPrimitiveValueMappings.h"
 #include "core/css/CSSUnicodeRangeValue.h"
 #include "core/css/CSSUnsetValue.h"
 #include "core/css/CSSVariableReferenceValue.h"
 #include "core/css/HashTools.h"
-#include "core/css/parser/CSSParserFastPaths.h"
-#include "core/css/parser/CSSParserIdioms.h"
 #include "core/css/parser/CSSParserLocalContext.h"
 #include "core/css/parser/CSSPropertyParserHelpers.h"
 #include "core/css/parser/CSSVariableParser.h"
 #include "core/css/properties/CSSPropertyAPI.h"
-#include "core/css/properties/CSSPropertyAlignmentUtils.h"
-#include "core/css/properties/CSSPropertyBackgroundUtils.h"
 #include "core/css/properties/CSSPropertyFontUtils.h"
-#include "core/frame/UseCounter.h"
-#include "core/layout/LayoutTheme.h"
-#include "platform/wtf/text/StringBuilder.h"
 
 namespace blink {
 
 using namespace CSSPropertyParserHelpers;
 
+class CSSIdentifierValue;
+
 CSSPropertyParser::CSSPropertyParser(
     const CSSParserTokenRange& range,
     const CSSParserContext* context,