enable video blit color accuracy by default

BUG=671344, 760132
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

Review-Url: https://chromiumcodereview.appspot.com/2874063002
Cr-Commit-Position: refs/heads/master@{#499721}
3 files changed