Android: Makes ScreenOrientationProvider public

Moves ScreenOrientationProvider to content_public, and removes
the corresponding DEPS exception rule.
ScreenOrientationProviderManager was merged to ScreenOrientationProvider
as it doesn't have to be a stand-alone manager class.

Bug: 617324
Change-Id: Iaf721713e15a145de731a50f295c5b1efb76235e
Reviewed-on: https://chromium-review.googlesource.com/1071129
Reviewed-by: Bo <boliu@chromium.org>
Reviewed-by: Ted Choc <tedchoc@chromium.org>
Commit-Queue: Jinsuk Kim <jinsukkim@chromium.org>
Cr-Commit-Position: refs/heads/master@{#562124}
10 files changed