Docked windows should preferably all have the same width. The width of a newly docked window is adjusted to match the windows already docked and failing that the windows already docked are adjusted to match the new window. Failing all that the docked windows are centered rather than being flush with the screen edge.
BUG=275806
TEST=ash_unittests --gtest_filter=*Dock*Width*
Review URL: https://chromiumcodereview.appspot.com/
23684029
git-svn-id: svn://svn.chromium.org/chrome/trunk/src@224869 0039d316-1c4b-4281-b951-d872f2087c98