Clean up forward declarations in Source/core/loader

Source/core/loader/DocumentLoader.h

Index: Source/core/loader/DocumentLoader.h
diff --git a/Source/core/loader/DocumentLoader.h b/Source/core/loader/DocumentLoader.h
index b3d6e8a2c78d8e6b9791514557db331a21a99d41..4110a5ccb2ec8544ba0364d43c5a2bb92e86452b 100644
--- a/Source/core/loader/DocumentLoader.h
+++ b/Source/core/loader/DocumentLoader.h
@@ -48,24 +48,15 @@ namespace blink {
 class WebThreadedDataReceiver;
 }
 
-namespace WTF {
-class SchedulePair;
-}
-
 namespace blink {
     class ApplicationCacheHost;
-    class ArchiveResource;
     class ArchiveResourceCollection;
     class ResourceFetcher;
-    class ContentFilter;
     class DocumentInit;
-    class FormState;
     class LocalFrame;
     class FrameLoader;
     class MHTMLArchive;
-    class Page;
     class ResourceLoader;
-    class SharedBuffer;
 
     class DocumentLoader : public RefCounted<DocumentLoader>, private RawResourceClient {
         WTF_MAKE_FAST_ALLOCATED;