Add option to disable MirrorCache.

Add option to disable MirrorCache.

R=yurys@chromium.org

Committed: https://code.google.com/p/v8/source/detail?r=21644

[yurys, 2014-06-03 13:27:17]

lgtm

https://codereview.chromium.org/307383002/diff/20001/src/debug.cc
File src/debug.cc (right):

https://codereview.chromium.org/307383002/diff/20001/src/debug.cc#newcode2462
src/debug.cc:2462: Factory* factory = isolate_->factory();
Just curious why is the advantage of this implementation compared to
ClearMirrorCache call?

https://codereview.chromium.org/307383002/diff/20001/src/mirror-debugger.js
File src/mirror-debugger.js (right):

https://codereview.chromium.org/307383002/diff/20001/src/mirror-debugger.js#n...
src/mirror-debugger.js:112: return mirror_cache_enabled_ ? mirror_cache_[handle]
: UNDEFINED;
I'd rather we threw an exception if mirror cache is disabled.

[Yang, 2014-06-03 14:22:04]

https://codereview.chromium.org/307383002/diff/20001/src/debug.cc
File src/debug.cc (right):

https://codereview.chromium.org/307383002/diff/20001/src/debug.cc#newcode2462
src/debug.cc:2462: Factory* factory = isolate_->factory();
On 2014/06/03 13:27:18, yurys wrote:
> Just curious why is the advantage of this implementation compared to
> ClearMirrorCache call?

Less overhead, and I think that two SetProperty is nicer than a GetProperty +
TryCall.

https://codereview.chromium.org/307383002/diff/20001/src/mirror-debugger.js
File src/mirror-debugger.js (right):

https://codereview.chromium.org/307383002/diff/20001/src/mirror-debugger.js#n...
src/mirror-debugger.js:112: return mirror_cache_enabled_ ? mirror_cache_[handle]
: UNDEFINED;
On 2014/06/03 13:27:18, yurys wrote:
> I'd rather we threw an exception if mirror cache is disabled.

Done.

[Yang, 2014-06-03 14:27:27]

Committed patchset #3 manually as r21644.