Minor comment update in stack_sampling_profiler.h

This is a cleanup CL following crrev.com/c/1114213.

Bug: 851163
Change-Id: I1e694737f26a3fa5e35ef7afe486e3866b3b86db
Reviewed-on: https://chromium-review.googlesource.com/1115283
Reviewed-by: Mike Wittman <wittman@chromium.org>
Commit-Queue: Xi Cheng <chengx@chromium.org>
Cr-Commit-Position: refs/heads/master@{#570497}
1 file changed