On Document disposal, only dispose of script runner.

On Document disposal, only dispose of script runner.

Reinstate the invariant that a Document always has a ScriptRunner
(m_scriptRunner), even after the document has been dispose()d.

The reason for disposing the Document's ScriptRunner is to clear
out back references that would otherwise cause the Document to
leak. Do just that, but don't destruct the now-empty ScriptRunner
object.

R=haraken
BUG=536796
Committed: https://crrev.com/9f0ccc18cedb41d2c1bbc4168f46c57a94451723
Cr-Commit-Position: refs/heads/master@{#351385}

[sof, 2015-09-29 15:36:49]

sigbjornf@opera.com changed reviewers:
+ haraken@chromium.org, tkent@chromium.org

[sof, 2015-09-29 15:36:50]

please take a look.

[haraken, 2015-09-29 15:45:20]

LGTM

[sof, 2015-09-29 17:49:26]

The CQ bit was checked by sigbjornf@opera.com

[commit-bot: I haz the power, 2015-09-29 17:49:54]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1380543002/20001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1380543002/20001

[commit-bot: I haz the power, 2015-09-29 19:29:41]

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

[commit-bot: I haz the power, 2015-09-29 19:29:42]

Try jobs failed on following builders:
  win_chromium_x64_rel_ng on tryserver.chromium.win (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.win/builders/win_chromium_x64_...)

[sof, 2015-09-29 19:30:21]

The CQ bit was checked by sigbjornf@opera.com

[commit-bot: I haz the power, 2015-09-29 19:31:06]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1380543002/20001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1380543002/20001

[commit-bot: I haz the power, 2015-09-29 20:10:48]

Committed patchset #2 (id:20001)

[commit-bot: I haz the power, 2015-09-29 20:11:34]

Patchset 2 (id:??) landed as
https://crrev.com/9f0ccc18cedb41d2c1bbc4168f46c57a94451723
Cr-Commit-Position: refs/heads/master@{#351385}