[Sync] Remove unneeded 'using syncer::' lines and 'syncer::' scopings

sync/internal_api/public/util/immutable.h

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // Immutable<T> provides an easy, cheap, and thread-safe way to pass
 // large immutable data around.
 //
 // For example, consider the following code:
 //
 //  typedef std::vector<LargeObject> LargeObjectList;
 //
 //   void ProcessStuff(const LargeObjectList& stuff) {
 //     for (LargeObjectList::const_iterator it = stuff.begin();
 //          it != stuff.end(); ++it) {
 //       ... process it ...
 //     }
 //   }
 //
 //   ...
 //
 //   LargeObjectList my_stuff;
 //   ... fill my_stuff with lots of LargeObjects ...
 //   some_loop->PostTask(FROM_HERE, base::Bind(&ProcessStuff, my_stuff));
 //
 // The last line incurs the cost of copying my_stuff, which is
 // undesirable.  Here's the above code re-written using Immutable<T>:
 //
-//   void ProcessStuff(
-//       const syncer::Immutable<LargeObjectList>& stuff) {
+//   void ProcessStuff(const Immutable<LargeObjectList>& stuff) {
 //     for (LargeObjectList::const_iterator it = stuff.Get().begin();
 //          it != stuff.Get().end(); ++it) {
 //       ... process it ...
 //     }
 //   }
 //
 //   ...
 //
 //   LargeObjectList my_stuff;
 //   ... fill my_stuff with lots of LargeObjects ...
@@ skipping 212 matching lines @@
 
 // Helper function to avoid having to write out template arguments.
 template <typename T>
 Immutable<T> MakeImmutable(T* t) {
   return Immutable<T>(t);
 }
 
 }  // namespace syncer
 
 #endif  // SYNC_UTIL_IMMUTABLE_H_