Hold a wakelock while retrieving reports

This attempts to fix an issue where the device will go to sleep while
retrieving a report. If this happens a report may contain inconsistent
timestamps.

Bug: 167329914
Test: m -j
Change-Id: Ibee08d95043759aa1114274378e4d72336174010
Merged-In: Ibee08d95043759aa1114274378e4d72336174010
(cherry picked from commit e0f4b3da)