Remove SimpleBroker and instead use the production broker implementation in tests.

mojo/edk/system/run_all_unittests.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.
 
 #include "base/bind.h"
 #include "base/command_line.h"
 #include "base/test/launcher/unit_test_launcher.h"
 #include "base/test/test_suite.h"
 #include "mojo/edk/embedder/embedder.h"
+#include "mojo/edk/test/multiprocess_test_helper.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 int main(int argc, char** argv) {
 // Silence death test thread warnings on Linux. We can afford to run our death
 // tests a little more slowly (< 10 ms per death test on a Z620).
 // On android, we need to run in the default mode, as the threadsafe mode
 // relies on execve which is not available.
 #if !defined(OS_ANDROID)
   testing::GTEST_FLAG(death_test_style) = "threadsafe";
 #endif
+  base::TestSuite test_suite(argc, argv);
+
+  // Must be run before mojo::edk::Init.
+  if (base::CommandLine::ForCurrentProcess()->HasSwitch(
+          mojo::edk::test::kBrokerHandleSwitch)) {
+    mojo::edk::PreInitializeChildProcess();
+  }
+
   mojo::edk::Init();
-  base::TestSuite test_suite(argc, argv);
   // TODO(use_chrome_edk): temporary to force new EDK.
   base::CommandLine::ForCurrentProcess()->AppendSwitch("--use-new-edk");
 
   return base::LaunchUnitTests(
       argc, argv,
       base::Bind(&base::TestSuite::Run, base::Unretained(&test_suite)));
 }