[Author: aharper]
[Author: aharper]

Move worker thread globals into the right #ifdef guard for SDK version.

R=dmaclach,thomasvl
APPROVED=thomasvl
DELTA=8  (4 added, 4 deleted, 0 changed)

jonreid/google-toolbox-for-mac,jonreid/google-toolbox-for-mac,jonreid/google-toolbox-for-mac