Merge "libbinder: remove handle 0 TODO" am: aad4dcfb am: 03ba0ff6

                //

                // Note that this is not race-free if the context manager

                // dies while this code runs.

                //

                // TODO: add a driver API to wait for context manager, or

                // stop special casing handle 0 for context manager and add

                // a driver API to get a handle to the context manager with

                // proper reference counting.

                IPCThreadState* ipc = IPCThreadState::self();