Enable -Wformat in linux, android, chromeos, cast builds.

tools/android/file_poller/file_poller.cc

 // Copyright 2014 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.
 
 // When run with 2 or more arguments the file_poller tool will open a port on
 // the device, print it on its standard output and then start collect file
 // contents.  The first argument is the polling rate in Hz, and the following
 // arguments are file to poll.
 // When run with the port of an already running file_poller, the tool will
 // contact the first instance, retrieve the sample and print those on its
@@ skipping 70 matching lines @@
   int n = transfer_to_buffer(fd_in, buffer, sizeof(buffer));
   safe_write(fd_out, buffer, n - 1);
   safe_write(fd_out, last ? "\n" : " ", 1);
 }
 
 // Acquire a sample and save it to the given file descriptor.
 void acquire_sample(int fd, const Context& context) {
   struct timeval tv;
   gettimeofday(&tv, NULL);
   char buffer[1024];
-  int n = snprintf(buffer, sizeof(buffer), "%d.%06d ", tv.tv_sec, tv.tv_usec);
+  int n = snprintf(buffer, sizeof(buffer), "%ld.%06ld ", tv.tv_sec, tv.tv_usec);
   safe_write(fd, buffer, n);
 
   for (int i = 0; i < context.nb_files; ++i)
     transfer_measurement(context.file_fds[i], fd, i == (context.nb_files - 1));
 }
 
 void poll_content(const Context& context) {
   // Create and bind the socket so that the port can be written to stdout.
   int sockfd = socket(AF_INET, SOCK_STREAM, 0);
   struct sockaddr_in socket_info;
@@ skipping 97 matching lines @@
     Context context;
     context.poll_rate = atoi(argv[1]);
     context.nb_files = argc - 2;
     context.file_fds = new int[context.nb_files];
     for (int i = 2; i < argc; ++i)
       context.file_fds[i - 2] = checked_open(argv[i]);
     poll_content(context);
   }
   return EXIT_SUCCESS;
 }