Remove muting at < 0.5x and > 4x; helps accessibility use cases.

Lets try this again; last time we had to revert due to hangs during
transitions between low to high rates, but this does not reproduce
anymore. Seemingly the hangs could have happened at any rate and
have hopefully been subsequently fixed.

BUG=289354
TEST=unittests pass, no hangs could be reproduced.

Cq-Include-Trybots: master.tryserver.chromium.android:android_optional_gpu_tests_rel;master.tryserver.chromium.linux:linux_optional_gpu_tests_rel;master.tryserver.chromium.mac:mac_optional_gpu_tests_rel;master.tryserver.chromium.win:win_optional_gpu_tests_rel
Change-Id: I9d40f55031185227a76831bbd594f0cb45510c44
Reviewed-on: https://chromium-review.googlesource.com/717177
Reviewed-by: Dan Sanders <sandersd@chromium.org>
Commit-Queue: Dale Curtis <dalecurtis@chromium.org>
Cr-Commit-Position: refs/heads/master@{#509159}
3 files changed