Refactor decoder support query utils

Until now, media/ decoder capabilities were described by
media/base/decode_capabilities.*. Embedders could override those
abilities via MediaClient. This meant 2 steps to query for
what configs were supported
1) if MediaClient exists, ask it
2) fallback to functions in decode_capabilites

We have two places where these steps should be followed:
MimeUtilInternal and WebMediaCapabilitiesClientImpl. Until now,
only MimeUtilInternal did both.

We anticipate a third caller (when creating FFmpegDemuxerStreams), so
the time is right to put these two steps into a utility function:
	bool IsSupported{Audio|Video}Type(...);

This is defined in a new file: media/base/supported_types.h. media/'s
default capabilities are also described in that file, via
	bool IsDefaultSupported*Type(...);

This change also renames the struct inputs to these APIs from
*Config to *Type. *Config was too close to *DecoderConfig and
*Type is a closer match to the web APIs we're trying to serve
(IsTypeSupported and CanPlayType).

Change-Id: I5c49d28f3d7ad9e824388cb346369795c3a621f9
Bug: 911823
Reviewed-on: https://chromium-review.googlesource.com/c/1361938
Reviewed-by: Sergey Volk <servolk@chromium.org>
Reviewed-by: John Abd-El-Malek <jam@chromium.org>
Reviewed-by: Thomas Guilbert <tguilbert@chromium.org>
Commit-Queue: Chrome Cunningham <chcunningham@chromium.org>
Cr-Commit-Position: refs/heads/master@{#614524}
17 files changed