Follow storage refactoring in system.

Also add entry point for SystemUI unmounting, and require permissions
when launching into those flows.

Bug: 19993667
Change-Id: I703d2e5f118848a2e2e96ce1d7f970e5705a288a

src/com/android/settings/deviceinfo/StorageWizardReady.java

@@ -34,7 +34,7 @@ public class StorageWizardReady extends StorageWizardBase {
 
         // TODO: handle mixed partition cases instead of just guessing based on
         // first volume type we encounter
-        for (String volId : mDisk.volumes) {
+        for (String volId : mDisk.volumeIds) {
             final VolumeInfo vol = mStorage.findVolumeById(volId);
             if (vol == null) continue;