[Android] Allows tabs to be exposed in stacking mode with a mouse

[Android] Allows tabs to be exposed in stacking mode with a mouse

Checks if a tab is fully visible before activating reorder mode
for mouse drags. This allows the staked mode to be still usable
with a mouse.

BUG=472318
Committed: https://crrev.com/c7e96732da26156fe16b15c6f98114f5b25326b1
Cr-Commit-Position: refs/heads/master@{#340994}

[varkha, 2015-07-29 18:24:08]

varkha@chromium.org changed reviewers:
+ dtrainor@chromium.org

[varkha, 2015-07-29 18:24:09]

dtrainor@, PTAL. This is one of the approaches to fix regression in
https://chromiumcodereview.appspot.com/1261443002/.
Thanks!

[David Trainor- moved to gerrit, 2015-07-29 20:57:56]

This workaround seems fine to me for now :).  I'd need to play with it a bit to
see what feels right.  Either that or we can loop in a UX designer for a well
rounded long term solution.

lgtm.

[varkha, 2015-07-29 21:01:57]

Thanks. I'll land it and watch for the feedback on this.

[varkha, 2015-07-29 21:02:01]

The CQ bit was checked by varkha@chromium.org

[commit-bot: I haz the power, 2015-07-29 21:03:34]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1259823003/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1259823003/1

[commit-bot: I haz the power, 2015-07-29 21:49:18]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-07-29 21:49:56]

Patchset 1 (id:??) landed as
https://crrev.com/c7e96732da26156fe16b15c6f98114f5b25326b1
Cr-Commit-Position: refs/heads/master@{#340994}