Clean up the useless GetAttributedSubstringFromRange() and the related IPC.

Clean up the useless GetAttributedSubstringFromRange() and the related IPC.

This is based on 2 CLs:
 - https://codereview.chromium.org/1313553006
 - https://codereview.chromium.org/1327743002

BUG=121917
Committed: https://crrev.com/fbadac5baf4b1d032782b7129088a29341de9598
Cr-Commit-Position: refs/heads/master@{#350182}

[Shu Chen, 2015-09-02 05:06:13]

shuchen@chromium.org changed reviewers:
+ palmer@chromium.org, sievers@chromium.org

[palmer, 2015-09-02 20:02:32]

LGTM.

Note that you don't need that TEST line in your CL description; that line is to
give the testing team an idea of what to look for. Nothing even gets to them
unless it has already compiled cleanly. :)

[no sievers, 2015-09-03 20:23:13]

lgtm

[Shu Chen, 2015-09-22 17:02:05]

The CQ bit was checked by shuchen@chromium.org

[Shu Chen, 2015-09-22 17:02:06]

The patchset sent to the CQ was uploaded after l-g-t-m from palmer@chromium.org,
sievers@chromium.org
Link to the patchset: https://codereview.chromium.org/1326763003/#ps40001
(title: " ")

[commit-bot: I haz the power, 2015-09-22 17:02:41]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1326763003/40001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1326763003/40001

[commit-bot: I haz the power, 2015-09-22 17:29:01]

Committed patchset #3 (id:40001)

[commit-bot: I haz the power, 2015-09-22 17:29:31]

Patchset 3 (id:??) landed as
https://crrev.com/fbadac5baf4b1d032782b7129088a29341de9598
Cr-Commit-Position: refs/heads/master@{#350182}