Messaging: Language cleanup

No unnecessary boxing, enhanced for loops, redundant checks and throws,
imports (removal, reordering), possible void returns

Change-Id: I7a8e1b2007e3b0906e01b41785c518d02c2f3fab

src/com/android/messaging/util/ChangeDefaultSmsAppHelper.java

@@ -104,7 +104,7 @@ public class ChangeDefaultSmsAppHelper {
         }
     }
 
-    private class ChangeSmsAppSettingRunnable implements Runnable {
+    private static class ChangeSmsAppSettingRunnable implements Runnable {
         private final Activity mActivity;
 
         public ChangeSmsAppSettingRunnable(final Activity activity) {