Add #include to fix compile errors on "Linux Perf (webkit.org)" bot.

sandbox/linux/seccomp/timestats.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.
 
 // Helper program to analyze the time that Chrome's renderers spend in system
 // calls. Start Chrome like this:
 //
 // SECCOMP_SANDBOX_DEBUGGING=1 chrome --enable-seccomp-sandbox 2>&1 | timestats
 //
 // The program prints CPU time (0-100%) spent within system calls. This gives
 // a general idea of where it is worthwhile to spend effort optimizing Chrome.
 //
 // Caveats:
 //  - there currently is no way to estimate what the overhead is for running
 //    inside of the sandbox vs. running without a sandbox.
 //  - we currently use a very simple heuristic to decide whether a system call
 //    is blocking or not. Blocking system calls should not be included in the
 //    computations. But it is quite possible for the numbers to be somewhat
 //    wrong, because the heuristic failed.
 //  - in order to collect this data, we have to turn on sandbox debugging.
 //    There is a measurable performance penalty to doing so. Production numbers
 //    are strictly better than the numbers reported by this tool.
 #include <set>
 #include <vector>
 
 #include <stdio.h>
+#include <stdlib.h>
 #include <string.h>
 #include <sys/time.h>
 #include <time.h>
 
 static const int kAvgWindowSizeMs  =    500;
 static const int kPeakWindowSizeMs = 2*1000;
 
 // Class containing information on a single system call. Most notably, it
 // contains the time when the system call happened, and the time that it
 // took to complete.
@@ skipping 144 matching lines @@
 
     // Extract the name of the system call
     *colon = '\000';
 
     // Add the data point and update the display
     data.addData(buf, ms);
   }
   puts("");
   return 0;
 }