Prevent unused-variable warnings in the CrOS build with gcc 4.6.

Prevent unused-variable warnings in the CrOS build with gcc 4.6.

BUG=none
TEST=trybots, local cros/arm build of chrome succeeds.


Committed: http://src.chromium.org/viewvc/chrome?view=rev&revision=110407

[Ami GONE FROM CHROMIUM, 2011-11-12 03:48:20]

jam: please review the CL, and specifically looking to you for
ipc/OWNERS-review. (rest of CL is not OWNERS-guarded)

zelidrag: cc'ing you as an FYI b/c of the instance of found_disk in the diff;
was that supposed to be hooked up to something?

nkostylev/flackr: cc'ing you as FYI that the idiom 
Foo* foo = f.release();
foo = NULL;
isn't an effective way to get around WARN_UNUSED_RESULT.  Instead use
ignore_result().

[Ami GONE FROM CHROMIUM, 2011-11-12 04:08:41]

Oops, my ipc/ change was crackfull.  A better fix is to fix the mismatched
IPC_BEGIN_MESSAGE_MAP/IPC_END_MESSAGE_MAP_EX pair in image_decoder.cc.  Happily,
jam@, svn blames you for that mismatch, so I feel ok leaving this review with
you :)
Updated patchset.

(for the curious, gcc-4.6 which cros just moved to appears to be stricter about
set-but-not-used variables, esp. when built directly, outside the usual emerge
setup)

[jam, 2011-11-14 18:42:56]

lgtm

[Ami GONE FROM CHROMIUM, 2011-11-14 18:46:17]

zelidrag: oops, missed that c/b/c/cros has an OWNERS, so I need your review, not
just FYI.

[Ami GONE FROM CHROMIUM, 2011-11-16 17:06:58]

davemoore: please OWNERS-review.

[DaveMoore, 2011-11-16 23:36:12]

lgtm

[commit-bot: I haz the power, 2011-11-16 23:39:03]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/fischman@chromium.org/8537032/3001

[commit-bot: I haz the power, 2011-11-17 00:52:32]

Change committed as 110407