Enable --nacl-gdb flag on Linux.

chrome/browser/nacl_host/test/mock_nacl_gdb.cc

 // Copyright (c) 2012 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 <cstdio>
 #include <cstring>
 
 #include "base/command_line.h"
 #include "base/environment.h"
 #include "base/file_util.h"
 #include "base/logging.h"
+#include "base/memory/scoped_ptr.h"
 #include "base/process_util.h"
 
 static const char kArgs[] = "--args";
 static const char kEvalCommand[] = "--eval-command";
 static const char kNaClIrt[] = "nacl-irt ";
 static const char kPass[] = "PASS";
+static const char kDump[] = "dump binary value ";
+static const char kAttach[] = "attach ";
+
+// Send message to child nacl_helper
+void SendMessage(const char* arg) {
+  const char* file_end = strchr(arg, ' ');
+  CHECK(file_end);
+  char buf = '\0';
+  file_util::WriteFile(FilePath(FilePath::StringType(arg, file_end)), &buf, 1);
+}
 
 int main(int argc, char** argv) {
   scoped_ptr<base::Environment> env(base::Environment::Create());
   std::string mock_nacl_gdb_file;
   env->GetVar("MOCK_NACL_GDB", &mock_nacl_gdb_file);
   file_util::WriteFile(FilePath::FromUTF8Unsafe(mock_nacl_gdb_file),
                        kPass, strlen(kPass));
   CHECK_GE(argc, 3);
   // First argument should be --eval-command.
   CHECK_EQ(strcmp(argv[1], kEvalCommand), 0);
   // Second argument should start with nacl-irt.
   CHECK_GE(strlen(argv[2]), strlen(kNaClIrt));
   CHECK_EQ(strncmp(argv[2], kNaClIrt, strlen(kNaClIrt)), 0);
   char* irt_file_name = &argv[2][strlen(kNaClIrt)];
   FILE* irt_file = fopen(irt_file_name, "r");
   // nacl-irt parameter must be a file name.
   PCHECK(irt_file);
   fclose(irt_file);
   int i = 3;
+  bool has_attach_cmd = false;
+  char* message_pipe = NULL;
   // Skip additional --eval-command parameters.
   while (i < argc) {
     if (strcmp(argv[i], kArgs) == 0) {
       i++;
       break;
     }
     if (strcmp(argv[i], kEvalCommand) == 0) {
       i += 2;
       // Command line shouldn't end with --eval-command switch without value.
       CHECK_LE(i, argc);
+      if (strncmp(argv[i - 1], kDump, sizeof(kDump) - 1) == 0) {
+        message_pipe = argv[i - 1] + sizeof(kDump) - 1;
+      } else if (strncmp(argv[i - 1], kAttach, sizeof(kAttach) - 1) == 0) {
+        has_attach_cmd = true;
+      }
       continue;
     }
     // Unknown argument.
     NOTREACHED() << "Invalid argument " << argv[i];
   }
+  if (has_attach_cmd) {
+    CHECK_EQ(i, argc);
+    CHECK(message_pipe);
+    // Test passed, so we can let NaCl launching to continue.
+    SendMessage(message_pipe);
+    return 0;
+  }
   // --args switch must be present.
   CHECK_LT(i, argc);
 
   CommandLine::StringVector arguments;
   for (; i < argc; i++) {
     arguments.push_back(
         CommandLine::StringType(argv[i], argv[i] + strlen(argv[i])));
   }
   CommandLine cmd_line(arguments);
   // Process must be launched successfully.
   PCHECK(base::LaunchProcess(cmd_line, base::LaunchOptions(), NULL));
   return 0;
 }