Makes mus::Window and mash::wm::WmWindowMus notify existing observers only

Makes mus::Window and mash::wm::WmWindowMus notify existing observers only

This matches what we do in aura, and is causing problems if I do otherwise.

BUG=603369
TEST=none
R=jamescook@chromium.org

Committed: https://crrev.com/5ad2a6e51685cab37866676afcec388c066f30fa
Cr-Commit-Position: refs/heads/master@{#394283}

[James Cook, 2016-05-17 23:20:10]

lgtm

[sky, 2016-05-17 23:28:02]

The CQ bit was checked by sky@chromium.org

[commit-bot: I haz the power, 2016-05-17 23:28:26]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1983343002/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1983343002/1

[commit-bot: I haz the power, 2016-05-18 00:29:50]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2016-05-18 00:31:56]

Description was changed from

==========
Makes mus::Window and mash::wm::WmWindowMus notify existing observers only

This matches what we do in aura, and is causing problems if I do otherwise.

BUG=603369
TEST=none
R=jamescook@chromium.org
==========

to

==========
Makes mus::Window and mash::wm::WmWindowMus notify existing observers only

This matches what we do in aura, and is causing problems if I do otherwise.

BUG=603369
TEST=none
R=jamescook@chromium.org

Committed: https://crrev.com/5ad2a6e51685cab37866676afcec388c066f30fa
Cr-Commit-Position: refs/heads/master@{#394283}
==========

[commit-bot: I haz the power, 2016-05-18 00:31:57]

Patchset 1 (id:??) landed as
https://crrev.com/5ad2a6e51685cab37866676afcec388c066f30fa
Cr-Commit-Position: refs/heads/master@{#394283}