Snap

Add APIs to override decoration managers and customize decorations (Take 2) #4952

Job	Run time
arches	1s
mir-libs (amd64)	18m 11s
mir-libs (armhf)	54m 8s
mir-libs (arm64)	55m 37s
snap (canonical/mir-test-tools, amd64)	14m 35s
snap (canonical/mir-test-tools, armhf)	21m 55s
snap (canonical/mir-test-tools, arm64)	23m 55s
snap (canonical/confined-shell-wip, amd64)	8m 21s
snap (canonical/confined-shell-wip, armhf)	17m 35s
snap (canonical/confined-shell-wip, arm64)	21m 9s
snap (canonical/ubuntu-frame, amd64)	6m 14s
snap (canonical/ubuntu-frame, armhf)	15m 31s
snap (canonical/ubuntu-frame, arm64)	17m 4s
snap (Miriway/Miriway, amd64)	8m 52s
snap (Miriway/Miriway, armhf)	17m 45s
snap (Miriway/Miriway, arm64)	21m 40s
	5h 22m 33s

Provide feedback