[media] Do not use SupportedProfiles for RTCVideoDecoderAdapter.

SupportedProfiles is a VDA feature and should not be used for
MojoVideoDecoder paths. This CL adds a replacement check via
GpuVideoAcceleratorFactories::IsDecoderConfigSupported(), and
deprecates RTCVideoDecoderFactory::GetSupportedFormats().

If RTC wants to add a dependency on
RTCVideoDecoderFactory::GetSupportedFormats() in the future, there
are a number of challenges related to asynchronicity that must be
solved. For example, reporting 'all supported' before the
GpuVideoAcceleratorFactories cache is filled can totally break a
connection in cases where there is no software fallback.

Bug: 857111
Change-Id: Iae5122f5c119dfe30e7d15e183dd21305214c4fb
Reviewed-on: https://chromium-review.googlesource.com/c/1372888
Commit-Queue: Dan Sanders <sandersd@chromium.org>
Reviewed-by: Emircan Uysaler <emircan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#618711}
8 files changed