Fix number counter will keep going after window losed focus.

Use Time pick in AlarmClock, long press on + or -, make an
incoming call or press power key to suspend the device,
after resumed, the counter will keep going without press.

Change-Id: I5e69d5e17d3be9aa78648e6f8e28665ec305b36f

Author: Tony Wu

core/java/android/widget/NumberPickerButton.java

@@ -85,4 +85,12 @@ private void cancelLongpress() {
             mNumberPicker.cancelDecrement();
         }
     }
+
+    public void onWindowFocusChanged(boolean hasWindowFocus) {
+        super.onWindowFocusChanged(hasWindowFocus);
+        if (!hasWindowFocus) {
+            cancelLongpress();
+        }
+    }
+
 }