Only initialize NSS in PpapiPluginMain on !USE_OPENSSL builds.

Only initialize NSS in PpapiPluginMain on !USE_OPENSSL builds.

This dates to https://chromiumcodereview.appspot.com/11411013 which was added
to resolve the ClearKey CDM. ClearKey uses routines from //crypto which may use
NSS. But it doesn't need NSS in the chimera build, so we should limit this to
!USE_OPENSSL builds.

(The tests in question have also since moved to browser_tests and out of
//content.)

BUG=506323
Committed: https://crrev.com/5b8de7cab29ba996a03d2862b59e3a4dc9e6559e
Cr-Commit-Position: refs/heads/master@{#337935}

[davidben, 2015-07-06 23:41:45]

davidben@chromium.org changed reviewers:
+ jorgelo@chromium.org

[Jorge Lucangeli Obes, 2015-07-07 03:51:51]

lgtm

[davidben, 2015-07-08 22:16:26]

The CQ bit was checked by davidben@chromium.org

[commit-bot: I haz the power, 2015-07-08 22:17:49]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1222103005/1

[commit-bot: I haz the power, 2015-07-08 23:02:50]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-07-08 23:03:44]

Patchset 1 (id:??) landed as
https://crrev.com/5b8de7cab29ba996a03d2862b59e3a4dc9e6559e
Cr-Commit-Position: refs/heads/master@{#337935}