Change to update panel positions after panels moved to the new collection when the unstacking happe…

Change to update panel positions after panels moved to the new collection when the unstacking happens

When the unstacking happens, we should first move the panels to the new collection and then update their positions. If we're update panel positions first, the existing stack window will enclose 2 sets of panels that are not aligned which causes the background window to be seen.

BUG=223155
TEST=existing tests

Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=195307

[Dmitry Titov, 2013-04-19 17:37:42]

lgtm

[jianli, 2013-04-19 22:14:31]

Committed patchset #1 manually as r195307 (presubmit successful).