Fix 5466678: use new setSystemUiVisibility() API to enable clock in statusbar

This fixes a bug where the clock wasn't being shown in the statusbar while
the music widget is showing.

Change-Id: Ic1c52c4ab7fa1490fe14ddafaf2c494bcf51866d
diff --git a/core/java/android/app/StatusBarManager.java b/core/java/android/app/StatusBarManager.java
index c5ee48d..7863102 100644
--- a/core/java/android/app/StatusBarManager.java
+++ b/core/java/android/app/StatusBarManager.java
@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
- 
+
 package android.app;
 
 import android.content.Context;
@@ -71,7 +71,9 @@
      */
     public void disable(int what) {
         try {
-            mService.disable(what, mToken, mContext.getPackageName());
+            if (mService != null) {
+                mService.disable(what, mToken, mContext.getPackageName());
+            }
         } catch (RemoteException ex) {
             // system process is dead anyway.
             throw new RuntimeException(ex);