gn: add Blink GC plugin options

gn: add Blink GC plugin options

The Blink GC clang plugin supports a couple of extra options which the
Blink GN configuration does not currently expose. Do so here, but without
depending on the 'flags' script used by the gyp build system
(tools/clang/scripts/blink_gc_plugin_flags.py).

Specifically, this adds the following Blink GN variables:

 - blink_gc_plugin_option_do_dump_graph [ = false ]
     emit JSON-serialized representation of class graph.
 - blink_gc_plugin_option_warn_unneeded_finalizer [ = false ]
     warn of unnecessary destructor usage.

TBR=thakis
BUG=

Committed: https://crrev.com/a0ad50c5a8899f8c8a579758d2c586b68d48d44a
Cr-Commit-Position: refs/heads/master@{#401568}

[sof, 2016-06-23 09:07:41]

sigbjornf@opera.com changed reviewers:
+ thakis@chromium.org

[sof, 2016-06-23 09:07:42]

please take a look.

Part 2 of https://codereview.chromium.org/2081543002/.

(https://codereview.chromium.org/2088373002/ appears to have landed ok..no
trouble reported by the chromium.fyi + chromium.webkit builders.)

[sof, 2016-06-23 09:07:45]

The CQ bit was checked by sigbjornf@opera.com

[commit-bot: I haz the power, 2016-06-23 09:07:59]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/2097433002/20001

[commit-bot: I haz the power, 2016-06-23 09:47:42]

Committed patchset #2 (id:20001)

[commit-bot: I haz the power, 2016-06-23 09:49:12]

Description was changed from

==========
gn: add Blink GC plugin options

The Blink GC clang plugin supports a couple of extra options which the
Blink GN configuration does not currently expose. Do so here, but without
depending on the 'flags' script used by the gyp build system
(tools/clang/scripts/blink_gc_plugin_flags.py).

Specifically, this adds the following Blink GN variables:

 - blink_gc_plugin_option_do_dump_graph [ = false ]
     emit JSON-serialized representation of class graph.
 - blink_gc_plugin_option_warn_unneeded_finalizer [ = false ]
     warn of unnecessary destructor usage.

TBR=thakis
BUG=
==========

to

==========
gn: add Blink GC plugin options

The Blink GC clang plugin supports a couple of extra options which the
Blink GN configuration does not currently expose. Do so here, but without
depending on the 'flags' script used by the gyp build system
(tools/clang/scripts/blink_gc_plugin_flags.py).

Specifically, this adds the following Blink GN variables:

 - blink_gc_plugin_option_do_dump_graph [ = false ]
     emit JSON-serialized representation of class graph.
 - blink_gc_plugin_option_warn_unneeded_finalizer [ = false ]
     warn of unnecessary destructor usage.

TBR=thakis
BUG=

Committed: https://crrev.com/a0ad50c5a8899f8c8a579758d2c586b68d48d44a
Cr-Commit-Position: refs/heads/master@{#401568}
==========

[commit-bot: I haz the power, 2016-06-23 09:49:13]

Patchset 2 (id:??) landed as
https://crrev.com/a0ad50c5a8899f8c8a579758d2c586b68d48d44a
Cr-Commit-Position: refs/heads/master@{#401568}