image/tree: Fix top image chip detection

Currently, image tree visualization doesn't properly detect chips for
parent images, only looking at child images. This patch fixes the issue
by checking both parent and child images when determining which chips to
display in the tree view.

Signed-off-by: Paweł Gronowski <pawel.gronowski@docker.com>

Author: vvoland

cli/command/image/tree.go

@@ -170,10 +170,16 @@ func getPossibleChips(view treeView) (chips []imageChip) {
 
 	var possible []imageChip
 	for _, img := range view.images {
+		details := []imageDetails{img.Details}
+
 		for _, c := range img.Children {
+			details = append(details, c.Details)
+		}
+
+		for _, d := range details {
 			for idx := len(remaining) - 1; idx >= 0; idx-- {
 				chip := remaining[idx]
-				if chip.check(&c.Details) {
+				if chip.check(&d) {
 					possible = append(possible, chip)
 					remaining = append(remaining[:idx], remaining[idx+1:]...)
 				}