gralloc: Add asynchronous lock/unlock API

The existing API exposed to clients for software lock/unlock forces the gralloc
implementation to complete these operations synchronously. This change adds new
entry points for lock/unlock functionality that is suited for use with Android's
explicit synchronisation concept. This provides scope for the gralloc module
to internally optimise the work it must do for lock/unlock and to hide this cost
from the client.

Change-Id: I6c41f4a532b705fc76c7777b2f04ea293506b381
Merge "gralloc: Add asynchronous lock/unlock API"
Revert "gralloc: Add asynchronous lock/unlock API"

This reverts commit 2861789f4febe67e39de449488681edf3e98b6e2.

Change-Id: I334b8ca9b9fdef510df514c18aabb6a593dfaa75
Merge "Revert "gralloc: Add asynchronous lock/unlock API""
gralloc: Add asynchronous lock/unlock API

The existing API exposed to clients for software lock/unlock forces the gralloc
implementation to complete these operations synchronously. This change adds new
entry points for lock/unlock functionality that is suited for use with Android's
explicit synchronisation concept. This provides scope for the gralloc module
to internally optimise the work it must do for lock/unlock and to hide this cost
from the client.

Change-Id: If4b1bb5490ab2b20d796214a7da8a96427cfe52d
Merge "gralloc: Add asynchronous lock/unlock API"
auto-merger: merge in from aosp/master