[Android] Round instead if truncate for selection coordinates

[Android] Round instead if truncate for selection coordinates

Composited selection coordinates are in floating pointer DIPs. However,
current APIs for manipulating the selection are all in integral
coordinates. This leads to cases where an adjusted selection can
chaotically hop across selection region boundaries.

Until all platforms adopt unified selection and we transition the APIs
to use floating point coordinates, use rounded coordinates when
manipulating the selection from the browser.

BUG=489852
Committed: https://crrev.com/f7bf4534d8d520cbb2d8f4e896beec4368067ed9
Cr-Commit-Position: refs/heads/master@{#330640}

[jdduke (slow), 2015-05-19 21:09:35]

jdduke@chromium.org changed reviewers:
+ boliu@chromium.org

[jdduke (slow), 2015-05-19 21:09:36]

PTAL, simplest fix we can cherry-pick...

[boliu, 2015-05-19 21:14:43]

lgtm

[jdduke (slow), 2015-05-19 22:28:26]

The CQ bit was checked by jdduke@chromium.org

[commit-bot: I haz the power, 2015-05-19 22:29:24]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1139043004/1

[commit-bot: I haz the power, 2015-05-19 22:37:01]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-05-19 22:38:31]

Patchset 1 (id:??) landed as
https://crrev.com/f7bf4534d8d520cbb2d8f4e896beec4368067ed9
Cr-Commit-Position: refs/heads/master@{#330640}