GitLab

Reland: Add accelerated video decoder interface, VP8 and H.264 implementations and hook up to V4L2SVDA.

This is a reland as the previous CL has an issue with BUILD.gn and failed gn build.

An AcceleratedVideoDecoder is a video decoder that requires support from an
external accelerator (typically a hardware accelerator) to partially
offload the decode process after parsing stream headers, and performing
reference frame and state management.

In this design, the hardware-independent decoder implementation interfaces
with a HW-specific Accelerator to offload last stages of the decode process.

Add the interface for AcceleratedVideoDecoder, decoders for VP8 and H264,
V4L2-specific Accelerators for VP8 and H264 and a common accelerator/client
class for V4L2.

TEST=vdatest VP8/H264, mp4 local video playback, apprtc decode
BUG=chrome-os-partner:33728
TBR=wuchengli@chromium.org,kcwu@chromium.org,owenlin@chromium.org,xhwang@chromium.org,scherkus@chromium.org,dalecurtis@chromium.org

Review URL: https://codereview.chromium.org/813693006

Cr-Commit-Position: refs/heads/master@{#311464}