[ppapi] Simple deadlock detector for proxy lock.

[ppapi] Simple deadlock detector for proxy lock.

base::lock provides a simple detector for single-thread deadlock in
debug mode.  Implement a similar approach for the proxy lock in debug
or release.

BUG=161286
Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=170513

[Scott Hess - ex-Googler, 2012-11-16 23:56:07]

Does this look sane?  I reverted an earlier patch and found that this seems to
fire exactly when the debug-mode base::lock fires.

It probably requires a dance around the static lock, but I wanted to float it
before the weekend.

[Scott Hess - ex-Googler, 2012-11-29 00:13:42]

Trung seemed ambiguously un-enthusiastic about this.  WDYT, then?

[brettw, 2012-11-29 23:44:33]

https://chromiumcodereview.appspot.com/11280041/diff/1/ppapi/shared_impl/prox...
File ppapi/shared_impl/proxy_lock.cc (right):

https://chromiumcodereview.appspot.com/11280041/diff/1/ppapi/shared_impl/prox...
ppapi/shared_impl/proxy_lock.cc:16: base::Lock own_lock;
Can we just use TLS to hold a bool? I think this will add a static initializer
which will force somebody to revert you.

[Scott Hess - ex-Googler, 2012-11-30 00:49:51]

Please Take Another Look?  Thanks.

https://chromiumcodereview.appspot.com/11280041/diff/1/ppapi/shared_impl/prox...
File ppapi/shared_impl/proxy_lock.cc (right):

https://chromiumcodereview.appspot.com/11280041/diff/1/ppapi/shared_impl/prox...
ppapi/shared_impl/proxy_lock.cc:16: base::Lock own_lock;
On 2012/11/29 23:44:33, brettw wrote:
> Can we just use TLS to hold a bool? I think this will add a static initializer
> which will force somebody to revert you.

I think this must be why you get paid the big bucks.

[brettw, 2012-11-30 05:05:07]

lgtm

[commit-bot: I haz the power, 2012-11-30 17:59:03]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/shess@chromium.org/11280041/3002

[commit-bot: I haz the power, 2012-11-30 19:44:54]

Change committed as 170513