Make it clear what last_sync_timestamp actually tracks. Update

chrome/browser/sync/notifier/base/linux/async_network_alive_linux.cc

 // Copyright (c) 2010 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 "chrome/browser/sync/notifier/base/async_network_alive.h"
 
 #include <sys/socket.h>
 #include <asm/types.h>
 #include <linux/netlink.h>
 #include <linux/rtnetlink.h>
@@ skipping 51 matching lines @@
     int result = select(max_fd + 1, &rdfs, NULL, NULL, NULL);
 
     if (result <= 0) {
       error_ = true;
       PLOG(ERROR) << "select() returned unexpected result " << result;
       close(fd);
       close(exit_pipe_[0]);
       return;
     }
 
-    // Since we recieved a change from the socket, read the change in.
+    // Since we received a change from the socket, read the change in.
     if (FD_ISSET(fd, &rdfs)) {
       char buf[4096];
       struct iovec iov = { buf, sizeof(buf) };
       struct sockaddr_nl sa;
 
       struct msghdr msg = { (void *)&sa, sizeof(sa), &iov, 1, NULL, 0, 0 };
       recvmsg(fd, &msg, 0);
     }
 
     close(fd);
@@ skipping 32 matching lines @@
  private:
   int exit_pipe_[2];
   DISALLOW_COPY_AND_ASSIGN(AsyncNetworkAliveLinux);
 };
 
 AsyncNetworkAlive* AsyncNetworkAlive::Create() {
   return new AsyncNetworkAliveLinux();
 }
 
 }  // namespace notifier