vaapi: Replace VLOG with DVLOG for levels >= 3

VLOG() has a high overhead due to pattern matching. Calling it per-frame accounts for ~0.3% of all cycles spent in Chrome on ChromeOS devices.

Bug: 489441

Cq-Include-Trybots: luci.chromium.try:android_optional_gpu_tests_rel;luci.chromium.try:linux_optional_gpu_tests_rel;luci.chromium.try:mac_optional_gpu_tests_rel;luci.chromium.try:win_optional_gpu_tests_rel
Change-Id: I5d6fc6d829601f6ad501e1676fd8114ab99d82c2
Reviewed-on: https://chromium-review.googlesource.com/1132422
Commit-Queue: Chong Jiang <chongjiang@chromium.org>
Reviewed-by: James Cook <jamescook@chromium.org>
Reviewed-by: Pawel Osciak <posciak@chromium.org>
Reviewed-by: Miguel Casas <mcasas@chromium.org>
Cr-Commit-Position: refs/heads/master@{#575370}
3 files changed