Improve GCM enum switch type safety

google_apis/gcm/engine/mcs_client.cc

 // Copyright 2013 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.
 
 #include "google_apis/gcm/engine/mcs_client.h"
 
 #include <stddef.h>
 #include <set>
 #include <utility>
 
@@ skipping 137 matching lines @@
 std::string MCSClient::GetStateString() const {
   switch(state_) {
     case UNINITIALIZED:
       return "UNINITIALIZED";
     case LOADED:
       return "LOADED";
     case CONNECTING:
       return "CONNECTING";
     case CONNECTED:
       return "CONNECTED";
-    default:
-      NOTREACHED();
-      return std::string();
   }
+  NOTREACHED();
+  return std::string();
 }
 
 MCSClient::MCSClient(const std::string& version_string,
                      base::Clock* clock,
                      ConnectionFactory* connection_factory,
                      GCMStore* gcm_store,
                      GCMStatsRecorder* recorder)
     : version_string_(version_string),
       clock_(clock),
       state_(UNINITIALIZED),
@@ skipping 791 matching lines @@
         reinterpret_cast<mcs_proto::DataMessageStanza*>(packet->protobuf.get());
     CollapseKey collapse_key(*data_message);
     if (collapse_key.IsValid())
       collapse_key_map_.erase(collapse_key);
   }
 
   return packet;
 }
 
 } // namespace gcm