Clean up forward declarations in Source/core/css

Source/core/css/resolver/StyleResolver.h

Index: Source/core/css/resolver/StyleResolver.h
diff --git a/Source/core/css/resolver/StyleResolver.h b/Source/core/css/resolver/StyleResolver.h
index 75b60e6796efc88f78515b7ecc700ea7fdd088e5..ce394cf7f5977be3b6432cbeb4596753cd4940fb 100644
--- a/Source/core/css/resolver/StyleResolver.h
+++ b/Source/core/css/resolver/StyleResolver.h
@@ -44,11 +44,7 @@
 namespace blink {
 
 class AnimatableValue;
-class AnimationTimeline;
-class CSSAnimationUpdate;
-class CSSFontSelector;
 class CSSRuleList;
-class CSSSelector;
 class CSSStyleSheet;
 class CSSValue;
 class ContainerNode;
@@ -56,12 +52,8 @@ class Document;
 class Element;
 class ElementRuleCollector;
 class Interpolation;
-class KeyframeList;
-class KeyframeValue;
 class MediaQueryEvaluator;
-class MediaQueryResult;
 class RuleData;
-class Settings;
 class StyleKeyframe;
 class StylePropertySet;
 class StyleResolverStats;