[Sync] Rename csync namespace to syncer

sync/syncable/mutable_entry.h

Index: sync/syncable/mutable_entry.h
diff --git a/sync/syncable/mutable_entry.h b/sync/syncable/mutable_entry.h
index 773531b3b57f4746d3964a7ccf30499080a72003..13fb515d4fef2154d305a280fe1659f14fafcd3c 100644
--- a/sync/syncable/mutable_entry.h
+++ b/sync/syncable/mutable_entry.h
@@ -9,7 +9,7 @@
 #include "sync/syncable/entry.h"
 #include "sync/syncable/metahandle_set.h"
 
-namespace csync {
+namespace syncer {
 class WriteNode;
 }
 
@@ -89,7 +89,7 @@ class MutableEntry : public Entry {
  private:
   friend class Directory;
   friend class WriteTransaction;
-  friend class csync::WriteNode;
+  friend class syncer::WriteNode;
 
   // Don't allow creation on heap, except by sync API wrappers.
   void* operator new(size_t size) { return (::operator new)(size); }