IPC Fuzzer: Initialize mojo in the replay process.

Without this, ChannelMojo doesn't work.

R=inferno@chromium.org, tsepez@chromium.org
TBR=jamesr@chromium.org
BUG=453571

Review URL: https://codereview.chromium.org/867903006

Cr-Commit-Position: refs/heads/master@{#314010}

tools/ipc_fuzzer/replay/DEPS

 include_rules = [
   "+chrome/common",
   "+content/public/common",
+  "+third_party/mojo/src/mojo/edk/embedder"
 ]

tools/ipc_fuzzer/replay/replay_process.cc

@@ -16,9 +16,21 @@
 #include "ipc/ipc_descriptors.h"
 #include "ipc/ipc_switches.h"
 #include "ipc/mojo/ipc_channel_mojo.h"
+#include "third_party/mojo/src/mojo/edk/embedder/configuration.h"
+#include "third_party/mojo/src/mojo/edk/embedder/embedder.h"
+#include "third_party/mojo/src/mojo/edk/embedder/simple_platform_support.h"
 
 namespace ipc_fuzzer {
 
+// TODO(morrita): content::InitializeMojo() should be used once it becomes
+// a public API. See src/content/app/mojo/mojo_init.cc
+void InitializeMojo() {
+  mojo::embedder::GetConfiguration()->max_message_num_bytes =
+      64 * 1024 * 1024;
+  mojo::embedder::Init(scoped_ptr<mojo::embedder::PlatformSupport>(
+      new mojo::embedder::SimplePlatformSupport()));
+}
+
 ReplayProcess::ReplayProcess()
     : io_thread_("Chrome_ChildIOThread"),
       shutdown_event_(true, false),
@@ -60,6 +72,8 @@ bool ReplayProcess::Initialize(int argc, const char** argv) {
              kPrimaryIPCChannel + base::GlobalDescriptors::kBaseDescriptor);
 #endif
 
+  InitializeMojo();
+
   return true;
 }