Remove some InterfacePtr<> methods which directly deal with message pipe handles.

examples/spinning_cube/gles2_client_impl.cc

Index: examples/spinning_cube/gles2_client_impl.cc
diff --git a/examples/spinning_cube/gles2_client_impl.cc b/examples/spinning_cube/gles2_client_impl.cc
index f6c05799df8851e03683cdd374936f224988f2ff..ce638ead891c0aca1c1c00a02186616feb9701e7 100644
--- a/examples/spinning_cube/gles2_client_impl.cc
+++ b/examples/spinning_cube/gles2_client_impl.cc
@@ -107,8 +107,8 @@ void GLES2ClientImpl::HandleInputEvent(const mojo::Event& event) {
 
 void GLES2ClientImpl::ContextCreated(mojo::CommandBufferPtr command_buffer) {
   context_ = MojoGLES2CreateContext(
-      command_buffer.PassMessagePipe().release().value(), &ContextLostThunk,
-      this, mojo::Environment::GetDefaultAsyncWaiter());
+      command_buffer.PassInterface().PassHandle().release().value(),
+      &ContextLostThunk, this, mojo::Environment::GetDefaultAsyncWaiter());
   MojoGLES2MakeCurrent(context_);
   cube_.Init();
   WantToDraw();