Use NOTREACHED_NORETURN() for parts of media/

This is based off of xhwang@'s crrev.com/c/4357862.

Also includes some code cleanup like transitions into equivalent CHECKs.

Bug: 851128
Low-Coverage-Reason: Modifying should-be unreachable code.
Cq-Include-Trybots: luci.chromium.try:win32-official,win-official,mac-official,linux-official,fuchsia-official,android-official
Change-Id: I4191747e61a917defb3753e49c4513d6ddd72a99
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/4522417
Reviewed-by: Alex Gough <ajgo@chromium.org>
Commit-Queue: Peter Boström <pbos@chromium.org>
Reviewed-by: Robert Sesek <rsesek@chromium.org>
Reviewed-by: Dale Curtis <dalecurtis@chromium.org>
Commit-Queue: Robert Sesek <rsesek@chromium.org>
Auto-Submit: Peter Boström <pbos@chromium.org>
Reviewed-by: Mark Foltz <mfoltz@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1144383}

diff --git a/media/gpu/vp9_decoder.cc b/media/gpu/vp9_decoder.cc
index 1e5bb2b3..af26ea05 100644
--- a/media/gpu/vp9_decoder.cc
+++ b/media/gpu/vp9_decoder.cc

@@ -81,8 +81,7 @@
     case VP9PROFILE_PROFILE3:
       return bit_depth == 10u || bit_depth == 12u;
     default:
-      NOTREACHED();
-      return false;
+      NOTREACHED_NORETURN();
   }
 }