Debugger: do not hold onto debug infos weakly.

Debugger: do not hold onto debug infos weakly.

SharedFunctionInfos that have a debug info must not be collected.
Otherwise we lose previously set break points. This means that
there is no need to hold onto debug infos weakly. The reason this
has not caused an issue up till now is that code flushing has been
disabled when the debugger is active.

R=ulan@chromium.org

Committed: https://crrev.com/48e38e569caa29d4a3a2cacda92cb2bf24221d4f
Cr-Commit-Position: refs/heads/master@{#29869}

[Yang, 2015-07-27 06:48:01]

The CQ bit was checked by yangguo@chromium.org

[Yang, 2015-07-27 06:48:02]

The CQ bit was unchecked by yangguo@chromium.org

[Yang, 2015-07-27 06:48:05]

The CQ bit was unchecked by yangguo@chromium.org

[Yang, 2015-07-27 06:48:08]

The CQ bit was checked by yangguo@chromium.org to run a CQ dry run

[commit-bot: I haz the power, 2015-07-27 06:48:23]

Dry run: CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1255793003/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1255793003/1

[commit-bot: I haz the power, 2015-07-27 07:16:56]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2015-07-27 07:16:57]

Dry run: This issue passed the CQ dry run.

[ulan, 2015-07-27 08:41:13]

lgtm

https://codereview.chromium.org/1255793003/diff/1/src/debug.cc
File src/debug.cc (right):

https://codereview.chromium.org/1255793003/diff/1/src/debug.cc#newcode1640
src/debug.cc:1640: DCHECK(debug_info_list_ != NULL);
s/NULL/nullptr

[Yang, 2015-07-27 10:52:52]

The CQ bit was checked by yangguo@chromium.org

[Yang, 2015-07-27 10:52:52]

The patchset sent to the CQ was uploaded after l-g-t-m from ulan@chromium.org
Link to the patchset: https://codereview.chromium.org/1255793003/#ps20001
(title: "rebase and address comments")

[commit-bot: I haz the power, 2015-07-27 10:52:57]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2015-07-27 10:52:58]

This CL has an open dependency (Issue 1256193002 Patch 1). Please resolve the
dependency and try again.

[Yang, 2015-07-27 11:11:00]

The CQ bit was checked by yangguo@chromium.org

[commit-bot: I haz the power, 2015-07-27 11:11:10]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1255793003/20001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1255793003/20001

[commit-bot: I haz the power, 2015-07-27 11:52:26]

Committed patchset #2 (id:20001)

[commit-bot: I haz the power, 2015-07-27 11:52:52]

Patchset 2 (id:??) landed as
https://crrev.com/48e38e569caa29d4a3a2cacda92cb2bf24221d4f
Cr-Commit-Position: refs/heads/master@{#29869}