Mojo Channel: Fix deferred proxy dispatch; support paused channels

ipc/ipc_mojo_bootstrap.h

Index: ipc/ipc_mojo_bootstrap.h
diff --git a/ipc/ipc_mojo_bootstrap.h b/ipc/ipc_mojo_bootstrap.h
index f18857a77d27b68c2e55fc8b2a7a0d0dc25b4dfe..fb71e8a14a1d4cfa6d7de12acc73d4599e2dd2e6 100644
--- a/ipc/ipc_mojo_bootstrap.h
+++ b/ipc/ipc_mojo_bootstrap.h
@@ -52,6 +52,12 @@ class IPC_EXPORT MojoBootstrap {
   // Start the handshake over the underlying message pipe.
   virtual void Connect() = 0;
 
+  // Stop queuing new messages and start transmitting them instead.
+  virtual void Start() = 0;
+
+  // Flush outgoing messages which were queued before Start().
+  virtual void Flush() = 0;
+
   virtual mojo::AssociatedGroup* GetAssociatedGroup() = 0;
 };