Introduce phantom weak handles in the API and use them internally for debug info

Introduce phantom weak handles in the API and use them internally for debug info

R=ulan@chromium.org, jochen@chromium.org
BUG=

Committed: https://code.google.com/p/v8/source/detail?r=25083

[Erik Corry, 2014-11-02 18:41:44]

erik.corry@gmail.com changed reviewers:
+ erik.corry@gmail.com

[Erik Corry, 2014-11-02 18:41:45]

https://codereview.chromium.org/687003005/diff/1/src/global-handles.cc
File src/global-handles.cc (right):

https://codereview.chromium.org/687003005/diff/1/src/global-handles.cc#newcod...
src/global-handles.cc:268: Handle<Object> handle(*object, isolate);
This CL is a reland of https://codereview.chromium.org/649563006/

This line has been changed from

Handle<Object> handle(object).

That caused the new handle to have the same backing global handle slot, which
didn't work with Blink, where some of the bindings reset the GetParameter handle
and then expect to still be able to use the GetValue handle.

I added a new test in test-api.cc, so that V8's own tests can catch this in
future (ResetWeakHandle).

[ulan, 2014-11-03 14:18:44]

ulan@chromium.org changed reviewers:
+ ulan@chromium.org

[ulan, 2014-11-03 14:18:44]

lgtm

[Erik Corry Chromium.org, 2014-11-03 17:27:38]

Committed patchset #1 (id:1) manually as 25083 (presubmit successful).