chrome: Cleanup class/struct forward declarations

chrome/browser/browsing_data/browsing_data_remover.h

Index: chrome/browser/browsing_data/browsing_data_remover.h
diff --git a/chrome/browser/browsing_data/browsing_data_remover.h b/chrome/browser/browsing_data/browsing_data_remover.h
index 2ec8d08df269c4dd6159067ef463634ffc791663..0f4e795643161513c8fb3e167ac469c384779670 100644
--- a/chrome/browser/browsing_data/browsing_data_remover.h
+++ b/chrome/browser/browsing_data/browsing_data_remover.h
@@ -45,8 +45,6 @@
 class BrowsingDataFilterBuilder;
 class BrowsingDataFlashLSOHelper;
 class BrowsingDataRemoverFactory;
-class HostContentSettingsMap;
-class IOThread;
 class Profile;
 class WebappRegistry;
 
@@ -60,10 +58,6 @@ class PluginDataRemover;
 class StoragePartition;
 }
 
-namespace net {
-class URLRequestContextGetter;
-}
-
 ////////////////////////////////////////////////////////////////////////////////
 // BrowsingDataRemover is responsible for removing data related to browsing:
 // visits in url database, downloads, cookies ...