Add missing include for sleep().

dm/DM.cpp

 /*
  * Copyright 2013 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "CrashHandler.h"
 #include "DMJsonWriter.h"
 #include "DMSrcSink.h"
@@ skipping 23 matching lines @@
 #endif
 
 #ifdef SKIA_PNG_PREFIXED
     // this must proceed png.h
     #include "pngprefix.h"
 #endif
 #include "png.h"
 
 #include <stdlib.h>
 
+#ifndef SK_BUILD_FOR_WIN32
+    #include <unistd.h>
+#endif
+
 DEFINE_string(src, "tests gm skp image", "Source types to test.");
 DEFINE_bool(nameByHash, false,
             "If true, write to FLAGS_writePath[0]/<hash>.png instead of "
             "to FLAGS_writePath[0]/<config>/<sourceType>/<sourceOptions>/<name>.png");
 DEFINE_bool2(pathOpsExtended, x, false, "Run extended pathOps tests.");
 DEFINE_string(matrix, "1 0 0 1",
               "2x2 scale+skew matrix to apply or upright when using "
               "'matrix' or 'upright' in config.");
 DEFINE_bool(gpu_threading, false, "Allow GPU work to run on multiple threads?");
 
@@ skipping 1107 matching lines @@
     #endif  // SK_PDF_IMAGE_STATS
     return 0;
 }
 
 #if !defined(SK_BUILD_FOR_IOS)
 int main(int argc, char** argv) {
     SkCommandLineFlags::Parse(argc, argv);
     return dm_main();
 }
 #endif