Increase OSX post-resume delay for new audio streams.

Still seem to be occasional reports of this happening, so increase
the post-resume delay to two seconds.

The UMA stat for OSX is still much higher than other platforms,
0.5% for OSX, but 0.01% for Windows.  I'll monitor the UMA values
to see if those values go down after landing this.

BUG=160920
TEST=none

Review URL: https://codereview.chromium.org/1230023009

Cr-Commit-Position: refs/heads/master@{#338970}
1 file changed