[Sensors] Reland: Align sensor reading updates and 'onchange' notification with rAF.

For all sensors new reading values are read and 'onchange' notfication is send from rAF callbacks, thus avoiding possible Critical Rendering Path interruption.

Before this change a timers were used and this could unnecessarily drain CPU and battery.

BUG=668052
BUG=606766

Committed: https://crrev.com/6b071fe7dc3bd64a2914eadd5c67b483d064a6cb
Cr-Commit-Position: refs/heads/master@{#439467}

patch from issue 2551223003 at patchset 140001 (http://crrev.com/2551223003#ps140001)

Review-Url: https://codereview.chromium.org/2589283003
Cr-Commit-Position: refs/heads/master@{#440208}
17 files changed