Use ChannelMojo between browser and service processes.

chrome/service/service_ipc_server.h

Index: chrome/service/service_ipc_server.h
diff --git a/chrome/service/service_ipc_server.h b/chrome/service/service_ipc_server.h
index 34ed7081b4637befc2b14cd3b0e9951b2f424944..47a704bed3f754e86bb624603b534f01f94896db 100644
--- a/chrome/service/service_ipc_server.h
+++ b/chrome/service/service_ipc_server.h
@@ -12,10 +12,12 @@
 
 #include "base/macros.h"
 #include "base/memory/scoped_vector.h"
+#include "base/single_thread_task_runner.h"
 #include "ipc/ipc_channel_handle.h"
 #include "ipc/ipc_listener.h"
 #include "ipc/ipc_sender.h"
 #include "ipc/ipc_sync_channel.h"
+#include "mojo/public/cpp/system/message_pipe.h"
 
 namespace base {
 
@@ -47,12 +49,14 @@ class ServiceIPCServer : public IPC::Listener, public IPC::Sender {
     // Called when the IPC channel is closed. A return value of true indicates
     // that the IPC server should continue listening for new connections.
     virtual bool OnIPCClientDisconnect() = 0;
+
+    // Called to create a message pipe to use for an IPC Channel connection.
+    virtual mojo::ScopedMessagePipeHandle CreateChannelMessagePipe() = 0;
   };
 
   ServiceIPCServer(
       Client* client,
       const scoped_refptr<base::SingleThreadTaskRunner>& io_task_runner,
-      const IPC::ChannelHandle& handle,
       base::WaitableEvent* shutdown_event);
   ~ServiceIPCServer() override;
 
@@ -88,13 +92,12 @@ class ServiceIPCServer : public IPC::Listener, public IPC::Sender {
 
   Client* client_;
   scoped_refptr<base::SingleThreadTaskRunner> io_task_runner_;
-  IPC::ChannelHandle channel_handle_;
   std::unique_ptr<IPC::SyncChannel> channel_;
   base::WaitableEvent* shutdown_event_;
   ScopedVector<MessageHandler> message_handlers_;
 
   // Indicates whether an IPC client is currently connected to the channel.
-  bool ipc_client_connected_;
+  bool ipc_client_connected_ = false;
 
   // Calculates histograms deltas.
   std::unique_ptr<base::HistogramDeltaSerialization>