Properly initialize variables in RequestContentScript::ScriptData

Properly initialize variables in RequestContentScript::ScriptData

POD members of RequestContentScript::ScriptData weren't being initialized,
which a) is really bad because who knows what they might have been, and b)
is bad because it makes Dr. Memory unhappy.  Fix it (and pull ScriptData into
the .cc while we're at it).

BUG=409865
Committed: https://crrev.com/08735d6ab39e788d287dc538f268f3c65d9c97c8
Cr-Commit-Position: refs/heads/master@{#292960}

[Devlin, 2014-09-02 17:03:51]

rdevlin.cronin@chromium.org changed reviewers:
+ jyasskin@chromium.org

[Devlin, 2014-09-02 17:03:52]

Jeffrey, can you take a quick look?

[Jeffrey Yasskin, 2014-09-02 17:09:29]

lgtm

[Devlin, 2014-09-02 17:16:34]

The CQ bit was checked by rdevlin.cronin@chromium.org

[commit-bot: I haz the power, 2014-09-02 17:16:54]

CQ is trying da patch. Follow status at

https://chromium-status.appspot.com/cq/rdevlin.cronin@chromium.org/531823002/...

[commit-bot: I haz the power, 2014-09-02 18:23:50]

Committed patchset #2 (id:20001) as c653e60740e08c9e8485daeb78918ad8778c73ac

[commit-bot: I haz the power, 2014-09-10 03:19:30]

Patchset 2 (id:??) landed as
https://crrev.com/08735d6ab39e788d287dc538f268f3c65d9c97c8
Cr-Commit-Position: refs/heads/master@{#292960}