Candidate fix for observe-window-after-free error in WindowTreeClientImpl::LocalSetCapture

Candidate fix for observe-window-after-free error in WindowTreeClientImpl::LocalSetCapture

R=sadrul@chromium.org
BUG=612447

[Mark Dittmer, 2016-05-17 14:07:06]

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

[commit-bot: I haz the power, 2016-05-17 14:07:22]

Dry run: CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1982333002/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1982333002/1

[commit-bot: I haz the power, 2016-05-17 14:16:24]

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

[commit-bot: I haz the power, 2016-05-17 14:16:25]

Dry run: Try jobs failed on following builders:
  chromeos_daisy_chromium_compile_only_ng on tryserver.chromium.linux
(JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.linux/builders/chromeos_daisy_...)

[sadrul, 2016-05-17 14:27:31]

mus::Window::Destroy() calls WindowTreeClientImpl::DestroyWindow(). We should
reset |capture_window_| in there. It looks like we do that correctly, but I
think there are cases where we destroy a mus::Window (using
mus::Window::LocalDestroy()) from some more places. One possibility is to call
WindowTreeClientImpl::DestroyWindow() from ~Window(), instead of from
Window::Destroy()

[Mark Dittmer, 2016-05-17 14:52:57]

Call client->DestroyWindow from Window dtor rather than from window->Destroy

[Mark Dittmer, 2016-05-17 14:53:23]

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

[commit-bot: I haz the power, 2016-05-17 14:53:36]

Dry run: CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1982333002/20001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1982333002/20001

[Mark Dittmer, 2016-05-17 15:16:47]

sadrul@chromium.org: New candidate fails some mash unit tests:
https://build.chromium.org/p/tryserver.chromium.linux/builders/linux_chromium....
Investigating now.

[commit-bot: I haz the power, 2016-05-17 15:26:03]

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

[commit-bot: I haz the power, 2016-05-17 15:26:04]

Dry run: Try jobs failed on following builders:
  linux_chromium_gn_chromeos_rel on tryserver.chromium.linux (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.linux/builders/linux_chromium_...)

[Mark Dittmer, 2016-05-17 15:45:27]

Observer-based fix

[Mark Dittmer, 2016-05-17 15:46:41]

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

[commit-bot: I haz the power, 2016-05-17 15:46:56]

Dry run: CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1982333002/40001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1982333002/40001

[commit-bot: I haz the power, 2016-05-17 15:57:44]

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

[commit-bot: I haz the power, 2016-05-17 15:57:45]

Dry run: Try jobs failed on following builders:
  chromeos_amd64-generic_chromium_compile_only_ng on tryserver.chromium.linux
(JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.linux/builders/chromeos_amd64-...)
  linux_chromium_gn_chromeos_rel on tryserver.chromium.linux (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.linux/builders/linux_chromium_...)

[Mark Dittmer, 2016-05-17 16:06:52]

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

[Mark Dittmer, 2016-05-17 16:06:57]

rebase

[commit-bot: I haz the power, 2016-05-17 16:07:11]

Dry run: CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1982333002/60001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1982333002/60001

[commit-bot: I haz the power, 2016-05-17 16:21:28]

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

[commit-bot: I haz the power, 2016-05-17 16:21:29]

Dry run: Try jobs failed on following builders:
  cast_shell_linux on tryserver.chromium.linux (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.linux/builders/cast_shell_linu...)
  linux_chromium_gn_chromeos_rel on tryserver.chromium.linux (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.linux/builders/linux_chromium_...)

[Mark Dittmer, 2016-05-17 17:41:55]

Fix extra ref to capture_window_

[Mark Dittmer, 2016-05-17 17:43:12]

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

[commit-bot: I haz the power, 2016-05-17 17:43:33]

Dry run: CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1982333002/80001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1982333002/80001

[Mark Dittmer, 2016-05-17 18:36:19]

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

[Mark Dittmer, 2016-05-17 18:36:20]

Guard observer's AddObserver invocation

[commit-bot: I haz the power, 2016-05-17 18:36:50]

Dry run: CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1982333002/100001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1982333002/100001

[Mark Dittmer, 2016-05-17 19:33:42]

sadrul@chromium.org: I'm advocating the current fix on the grounds that it works

[commit-bot: I haz the power, 2016-05-17 19:52:31]

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

[commit-bot: I haz the power, 2016-05-17 19:52:32]

Dry run: This issue passed the CQ dry run.