[Sync] Remove now-obsolete FastDump class

chrome/browser/sync/syncable/syncable_id.cc

Index: chrome/browser/sync/syncable/syncable_id.cc
diff --git a/chrome/browser/sync/syncable/syncable_id.cc b/chrome/browser/sync/syncable/syncable_id.cc
index 60cf8c957b955019455e7b3b5705f720521baa40..766289b176637a56365bad2536de27b844ea0870 100644
--- a/chrome/browser/sync/syncable/syncable_id.cc
+++ b/chrome/browser/sync/syncable/syncable_id.cc
@@ -19,12 +19,6 @@ ostream& operator<<(ostream& out, const Id& id) {
   return out;
 }
 
-using browser_sync::FastDump;
-FastDump& operator<<(FastDump& dump, const Id& id) {
-  dump.out_->sputn(id.s_.data(), id.s_.size());
-  return dump;
-}
-
 string Id::GetServerId() const {
   // Currently root is the string "0". We need to decide on a true value.
   // "" would be convenient here, as the IsRoot call would not be needed.