Reland: Window.postMessage() to self can cause document leaks

Reland: Window.postMessage() to self can cause document leaks

When a script does Window.postMessage() a PostMessageTimer object is
stored in the LocalDOMWindow until the message has been delivered, or
until it is cleared in the destructor of LocalDOMWindow. When a
LocalDOMWindow is reset the remaining messages will not be
delivered. Any PostMessageTimer objects alive at that point will be kept
until the LocalDOMWindow is destroyed. Unfortunately, the
PostMessageTimer objects keeps a reference to the source window. If both
the source and destination window of the message is the same, the
PostMessageTimer can keep that LocalDOMWindow from getting destroyed.

Removing the PostMessageTimers when stop() is invoked fixes the problem.

BUG=500821, 499692
Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=197252

[landell, 2015-06-16 10:08:53]

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

[landell, 2015-06-16 10:11:48]

@reviewers: PTAL
This adds fix for crash regression issue 499692, incorporating sigbjorn's test
case.

The diffs of the expected.txt files looks really wierd so I am not sure if I did
something wrong.

[haraken, 2015-06-16 15:58:31]

LGTM

[landell, 2015-06-17 09:04:48]

The CQ bit was checked by landell@opera.com

[commit-bot: I haz the power, 2015-06-17 09:05:08]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1186093003/1

[commit-bot: I haz the power, 2015-06-17 11:55:21]

Committed patchset #1 (id:1) as
https://src.chromium.org/viewvc/blink?view=rev&revision=197252