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/StorageVolumePreference.java

@@ -45,7 +45,7 @@ public class StorageVolumePreference extends Preference {
         mVolume = volume;
 
         setKey(volume.id);
-        setTitle(mStorageManager.getBestVolumeDescription(volume.id));
+        setTitle(mStorageManager.getBestVolumeDescription(volume));
 
         switch (volume.state) {
             case VolumeInfo.STATE_MOUNTED:
@@ -83,7 +83,7 @@ public class StorageVolumePreference extends Preference {
     private final View.OnClickListener mUnmountListener = new OnClickListener() {
         @Override
         public void onClick(View v) {
-            new UnmountTask(getContext(), mVolume.id).execute();
+            new UnmountTask(getContext(), mVolume).execute();
         }
     };
 }