content: Remove unused speex related code.

content: Remove unused speex related code.

With the discussion of third_party/speex/OWNERS in chromium-dev
mailing list we ended up turning out that this code was actually not used.

https://groups.google.com/a/chromium.org/d/topic/chromium-dev/tBiPPpqfku4/discussion

BUG=513929
TEST=content_unittests
R=philip@opera.com,brettw@chromium.org

Committed: https://crrev.com/152a9729a7d1adb8582b4bec8ccf8f797c6f6987
Cr-Commit-Position: refs/heads/master@{#340637}

[tfarina, 2015-07-27 12:01:55]

tfarina@chromium.org changed reviewers:
+ philipj@opera.com
- philip@opera.com, tommi@chromium.org

[philipj_slow, 2015-07-27 12:19:37]

lgtm

I also see some matches for "speex" in build/gn_migration.gypi and
build/linux/unbundle/, can those also be nuked?

[tfarina, 2015-07-27 18:32:23]

tfarina@chromium.org changed reviewers:
+ brettw@chromium.org

[tfarina, 2015-07-27 18:32:23]

+Brett for review!

[brettw, 2015-07-27 19:17:49]

lgtm

[tfarina, 2015-07-28 03:03:11]

The CQ bit was checked by tfarina@chromium.org

[tfarina, 2015-07-28 03:03:11]

The patchset sent to the CQ was uploaded after l-g-t-m from philipj@opera.com
Link to the patchset: https://codereview.chromium.org/1257923002/#ps60001
(title: "rm more references")

[commit-bot: I haz the power, 2015-07-28 03:03:22]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1257923002/60001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1257923002/60001

[commit-bot: I haz the power, 2015-07-28 04:04:00]

Committed patchset #4 (id:60001)

[commit-bot: I haz the power, 2015-07-28 04:05:06]

Patchset 4 (id:??) landed as
https://crrev.com/152a9729a7d1adb8582b4bec8ccf8f797c6f6987
Cr-Commit-Position: refs/heads/master@{#340637}