libui: add notes to registerBuffer(buffer_handle_t)

The method is semi-broken on gralloc0 devices.  It calls down to
Gralloc1On0Adapter::managementHook, which will return
GRALLOC1_ERROR_BAD_HANDLE when the handle is received from a remote
process.

Test: make
Change-Id: Ia0ca2b51e38e8afe66a917ca7fe2282db3968f53
2 files changed