Improve grammar in some comments.

google_apis/gcm/engine/mcs_client.h

 // 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.
 
 #ifndef GOOGLE_APIS_GCM_ENGINE_MCS_CLIENT_H_
 #define GOOGLE_APIS_GCM_ENGINE_MCS_CLIENT_H_
 
 #include <stdint.h>
 
 #include <deque>
@@ skipping 137 matching lines @@
   int GetResendQueueSize() const;
 
   // Returns text representation of the state enum.
   std::string GetStateString() const;
 
   // Updates the timer used by |heartbeat_manager_| for sending heartbeats.
   void UpdateHeartbeatTimer(std::unique_ptr<base::Timer> timer);
 
   // Allows a caller to set a heartbeat interval (in milliseconds) with which
   // the MCS connection will be monitored on both ends, to detect device
-  // presence. In case the newly set interval is less then the current one,
+  // presence. In case the newly set interval is smaller than the current one,
   // connection will be restarted with new heartbeat interval. Valid values have
   // to be between GetMax/GetMinClientHeartbeatIntervalMs of HeartbeatManager,
   // otherwise the setting won't take effect.
   void AddHeartbeatInterval(const std::string& scope, int interval_ms);
   void RemoveHeartbeatInterval(const std::string& scope);
 
   HeartbeatManager* GetHeartbeatManagerForTesting() {
     return &heartbeat_manager_;
   }
 
@@ skipping 139 matching lines @@
   GCMStatsRecorder* recorder_;
 
   base::WeakPtrFactory<MCSClient> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(MCSClient);
 };
 
 } // namespace gcm
 
 #endif  // GOOGLE_APIS_GCM_ENGINE_MCS_CLIENT_H_