Remove GTalk/O1D plugins and related code

Remove GTalk/O1D plugins and related code

This removes some special-case code used to register and load
gtbp and o1d PPAPI plugins on Linux and ChromeOS. It also removes
infrastructure used to launch these plugins.

TEST=Run PDF (out-of-process) and NaCl (in-process) plugins
BUG=392002
Committed: https://crrev.com/01d8f26f28aba73ebd4346e296b947a2b939a1fb
Cr-Commit-Position: refs/heads/master@{#324131}

[jam, 2014-07-14 22:53:57]

lgtm, woohoo! (I realize you haven't published this yet, but if I don't review
it now, I might miss it later when you do since the link will appear visited)

[piman, 2014-07-14 23:07:24]

lgtm

[Josh Horwich, 2015-02-20 23:25:01]

New patchsets have been uploaded after l-g-t-m from
jam@chromium.org,piman@chromium.org

[Josh Horwich, 2015-03-02 19:04:22]

The CQ bit was checked by jhorwich@chromium.org

[commit-bot: I haz the power, 2015-03-02 19:05:18]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/374773002/40001

[Josh Horwich, 2015-03-02 19:51:54]

The CQ bit was unchecked by jhorwich@chromium.org

[Josh Horwich, 2015-04-07 21:00:59]

The CQ bit was checked by jhorwich@chromium.org

[commit-bot: I haz the power, 2015-04-07 21:01:46]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/374773002/60001

[commit-bot: I haz the power, 2015-04-07 22:01:58]

Committed patchset #4 (id:60001)

[commit-bot: I haz the power, 2015-04-07 22:02:53]

Patchset 4 (id:??) landed as
https://crrev.com/01d8f26f28aba73ebd4346e296b947a2b939a1fb
Cr-Commit-Position: refs/heads/master@{#324131}