This change makes BufferQueue derive the min undequeued buffer count from a max
acquired buffer count that is set by the consumer. This value may be set at
any time that a producer is not connected to the BufferQueue rather than at
BufferQueue construction time.
Change-Id: Icf9f1d91ec612a079968ba0a4621deffe48f4e22
BufferItemConsumer allows for acquiring BufferQueue's BufferItems,
which contain all the data and metadata the BufferQueue has for a
given graphics buffer.
This consumer is useful when direct access to the native buffer_handles
is needed by the client.
Also includes a minor cleanup of CpuConsumer's use of 'virtual'.
Bug: 6243944
Change-Id: If7dc4192b15ac499555f1eda42a85140f2434795