C2VDAComponent: support VP9 show_existing_frame.

In VP9 spec, the reference frame can be displayed more than once. We
changed the Chrome VDA implementation that passes the same output
buffer multiple times directly. This CL changed the C2VDAComponent
implementation according to this.

When output buffer is returned from accelerator (onOutputBufferDone), the
output buffer info will be queued into the FIFO |mPendingBuffersToWork|, and
component calls sendOutputBufferToWorkIfAny() to dequeue the FIFO to put output
buffer to its corresponding work as many as possible.

|mUndequeuedBlockIds| is introduced to store the buffer ID which will be
displayed right before the current buffer with the size of undequeued buffer
count for display. While dequeueing the FIFO if the current buffer ID could be
found in |mUndequeuedBlockIds|, there is no way to show this frame and we will
drop this frame immediately. Otherwise, the FIFO is temporarily blocked until
the current buffer is owned by component.

Bug: 110968122
Test: CtsMediaTestCases android.media.cts.DecoderConformanceTest#testVP9Other
on Kevin w/ Codec2.0 decoder

Change-Id: I228e42a76bff6f88af8c0d0a6aa795cfba356bd1
(cherry picked from commit 0af04055489cb9c0b9b3933969f56ac6c7c25e17)