Add support for video peek in Codec2

Video peek is a feature that enables displaying the first video frame
of a video stream decoded by a codec configured in tunnel mode.
This commit adds support for video peek to Codec2-based codecs.

Test: atest android.media.cts.DecoderTest
Merged-In: I74f0b6de2161f563a80b33f1bb3d6ff961de09b6
Merged-In: If8bc83f93d5cf12c1138c467e3152eafc3e92015
Merged-In: I298e27b1024440ea353f8a1db2afdabdb695f702

Change-Id: I533917908a7050c760374c7b607dd736ec173339