Test for --nacl-gdb functionality.

chrome/browser/nacl_host/mock_nacl_gdb.cc

+// Copyright (c) 2012 The Chromium Authors. All rights reserved.

[Mark Seaborn, 2012/03/13 01:05:20]

I think this file belongs in a directory with "test" in its name. 
"nacl_host/test/*" perhaps?

[halyavin, 2012/03/13 12:48:27]

Done.

+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include <cstdio>
+#include <cstring>
+
+#include "base/command_line.h"
+#include "base/process_util.h"
+
+const char kArgs[] = "--args";
+const char kEvalCommand[] = "--eval-command";
+const char kNaClIrt[] = "nacl-irt ";
+
+int main(int argc, char** argv) {
+  if (argc < 3) {
+    // Too few arguments.
+    return 1;

[Mark Seaborn, 2012/03/13 01:05:20]

Having different numbers for each failure is weird.  Can you just use CHECK()
for each check instead, assuming it works OK in this context?

[halyavin, 2012/03/13 12:48:27]

Done.

+  }
+  if (strcmp(argv[1], kEvalCommand) != 0) {
+    // First argument should be --eval-command.
+    return 2;
+  }
+  if (strlen(argv[2]) < strlen(kNaClIrt)) {
+    // Second argument should start with nacl-irt.
+    return 3;
+  }
+  if (strncmp(argv[2], kNaClIrt, strlen(kNaClIrt)) != 0) {
+    // Second argument should start with nacl-irt.
+    return 4;
+  }
+  char* irtFileName = &argv[2][strlen(kNaClIrt)];

[brettw, 2012/03/13 05:57:49]

style: irt_file_name (no caps in var names)

[halyavin, 2012/03/13 12:48:27]

Done.

+  FILE* irtFile = fopen(irtFileName, "r");

[brettw, 2012/03/13 05:57:49]

Ditto

[halyavin, 2012/03/13 12:48:27]

Done.

+  if (irtFile == NULL) {
+    // nacl-irt parameter must be a file name.
+    return 5;
+  }
+  fclose(irtFile);
+  int i = 3;
+  // Skip additional --eval-command parameters.
+  while (i < argc) {
+    if (strcmp(argv[i], kArgs) == 0) {
+      i++;
+      break;
+    }
+    if (strcmp(argv[i], kEvalCommand) == 0) {
+      i += 2;
+      if (i > argc) {
+        // Command line ends with --eval-command switch without value.
+        return 6;
+      }
+    }
+    // Unknown argument
+    return 7;
+  }
+  if (i >= argc) {
+    // --args not found.
+    return 8;
+  }
+
+  CommandLine::StringVector arguments;
+  for (; i < argc; i++) {
+    arguments.push_back(
+        CommandLine::StringType(argv[i], argv[i] + strlen(argv[i])));
+  }
+  CommandLine cmd_line(arguments);
+  if (!base::LaunchProcess(cmd_line, base::LaunchOptions(), NULL)) {
+    // process is not launched successfully
+    return 9;
+  }
+  return 0;
+}