ARC IME: remove titlebar offset hack.
ARC IME: remove titlebar offset hack.

A lot faster than I first thought, but the Android side change has
happened and now the ARC apps can report the correct coordinates
by themselves own. We don't need to add extra offset here any more.

BUG=none
TEST=manually verified.

Review URL: https://codereview.chromium.org/1884873002

Cr-Commit-Position: 972c6d2dc6dd5efdad1377c0d224e03eb8f276f7@{#387181}

axinging/chromium-crosswalk,axinging/chromium-crosswalk,axinging/chromium-crosswalk,axinging/chromium-crosswalk,axinging/chromium-crosswalk,axinging/chromium-crosswalk,axinging/chromium-crosswalk,axinging/chromium-crosswalk,axinging/chromium-crosswalk,axinging/chromium-crosswalk,axinging/chromium-crosswalk