Pepper: Reduce includes in generated thunks.

Pepper: Reduce includes in generated thunks.

There are some unnecessary includes in generated thunks. We should remove these
for clarity, and (hopefully) to reduce build time. A small test showed that
ppb_view_thunk.cc built 18% faster after the change, but that's well within the
noise on my local system.

BUG=334727
Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=245111

[Nico, 2014-01-15 18:04:20]

Awesome!

(re noise: I usually do min-of-3-builds build times before/after, this tends to
be relatively stable)

[dmichael (off chromium), 2014-01-15 18:10:44]

Nice! lgtm, assuming trybots like it

[teravest, 2014-01-15 18:23:21]

Doing min-of-3-builds on just obj/ppapi/thunk/ppapi_shared.ppb_view_thunk.o:

Before change:
1.03s user

After change:
0.97s user

Not very significant, about 5%. 

I'm still surprised at how long these take, I'll poke around and see if I can
speed these up.

[commit-bot: I haz the power, 2014-01-15 18:48:59]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/teravest@chromium.org/137353003/1

[commit-bot: I haz the power, 2014-01-16 04:34:39]

Change committed as 245111