Fix build error in release mode.

Fix build error in release mode.

I used a mix of NDEBUG and DHECK, but I didn't realise
that DCHECKs are still compiled in release builds, and
that the try bots don't catch this.

Updated to use base::NonThreadSafe, which is both
simpler and safer.

TBR=kbr@chromium.org
Committed: http://src.chromium.org/viewvc/chrome?view=rev&revision=99650

[lain Merrick, 2011-09-05 13:35:06]

I couldn't get hold of a sheriff, so I opened the tree myself and submitted this
TBR on kbr (who is in content/renderer/gpu/OWNER). Hope that's okay.

[greggman, 2011-09-06 16:43:25]

On 2011/09/05 13:35:06, Iain Merrick wrote:
> I couldn't get hold of a sheriff, so I opened the tree myself and submitted
this
> TBR on kbr (who is in content/renderer/gpu/OWNER). Hope that's okay.

Wait, seriously? DCHECK is compiled into release? I have some seriously heavy
DCHECKS here and there. Like DCHECK(somemap.find(thing) != somemap.end());

D = DEBUG. Shouldn't that be debug only?

[lain Merrick, 2011-09-06 16:49:37]

On 2011/09/06 16:43:25, greggman wrote:
> On 2011/09/05 13:35:06, Iain Merrick wrote:
> > I couldn't get hold of a sheriff, so I opened the tree myself and submitted
> this
> > TBR on kbr (who is in content/renderer/gpu/OWNER). Hope that's okay.
> 
> Wait, seriously? DCHECK is compiled into release? I have some seriously heavy
> DCHECKS here and there. Like DCHECK(somemap.find(thing) != somemap.end());
> 
> D = DEBUG. Shouldn't that be debug only?

I'm looking at base/logging.h, lines 536-551:

// In order to have optimized code for official builds, remove DLOGs and
// DCHECKs.
#define ENABLE_DLOG 0
#define ENABLE_DCHECK 0

#elif defined(NDEBUG)
// Otherwise, if we're a release build, remove DLOGs but not DCHECKs
// (since those can still be turned on via a command-line flag).
#define ENABLE_DLOG 0
#define ENABLE_DCHECK 1

#else
// Otherwise, we're a debug build so enable DLOGs and DCHECKs.
#define ENABLE_DLOG 1
#define ENABLE_DCHECK 1
#endif

It's even trickier than I thought. DCHECKs are included in normal release
builds, but not official builds.