Fix ipc fuzzer null pointer crash due to wrong order of mojo initialization.

TBR=morrita@chromium.org,tsepez@chromium.org
BUG=453571

Review URL: https://codereview.chromium.org/872673008

Cr-Commit-Position: refs/heads/master@{#314054}

tools/ipc_fuzzer/replay/replay_process.cc

@@ -63,6 +63,9 @@ bool ReplayProcess::Initialize(int argc, const char** argv) {
   settings.log_file = FILE_PATH_LITERAL("ipc_replay.log");
   logging::InitLogging(settings);
 
+  // Make sure to initialize Mojo before starting the IO thread.
+  InitializeMojo();
+
   io_thread_.StartWithOptions(
       base::Thread::Options(base::MessageLoop::TYPE_IO, 0));
 
@@ -72,8 +75,6 @@ bool ReplayProcess::Initialize(int argc, const char** argv) {
              kPrimaryIPCChannel + base::GlobalDescriptors::kBaseDescriptor);
 #endif
 
-  InitializeMojo();
-
   return true;
 }