linux: turn on -Wextra

linux: turn on -Wextra

This is a followup to an earlier change (r38266) which did most of the
warning-related cleanup.  This one just flips the flag, and fixes some
new warnings that crept in during the window while the flag was off.

BUG=34160
Committed: http://src.chromium.org/viewvc/chrome?view=rev&revision=42688

[Daniel Erat, 2010-03-11 22:55:18]

(superseded by 746001, so closing)

[Evan Martin, 2010-03-15 21:31:54]

reusing old change since git-cl is confused

[Markus (顧孟勤), 2010-03-15 21:36:21]

http://codereview.chromium.org/597023/diff/4001/5004
File sandbox/linux/seccomp/sandbox_impl.h (left):

http://codereview.chromium.org/597023/diff/4001/5004#oldcode271
sandbox/linux/seccomp/sandbox_impl.h:271: if (len < 0) {
We are probably better off to still have a sanity check here. How about:

  if (reinterpret_cast<ssize_t>(len) < 0) {
    ...

If anybody ever tries to read that much data, it is OK for us to fail, I think.
I couldn't think of any reason why the renderers would need to do this. And the
sandbox clearly doesn't need to do this, either.

[Evan Martin, 2010-03-15 21:42:51]

ok, uploaded

[Markus (顧孟勤), 2010-03-15 21:51:36]

LGTM

[Daniel Erat, 2010-03-15 22:03:46]

LGTM

[Evan Martin, 2010-03-16 00:17:49]

sorry, more changes (see patchset 4)

[Daniel Erat, 2010-03-16 00:22:17]

LGTM