[BUG] fix NullPointerException in Notification.java

https://code.google.com/p/android/issues/detail?id=252835

Test: null

Change-Id: I6c575686c75b02ac938f35622b522fff25403c29
Signed-off-by: liangweikang <liangweikang900911@gmail.com>
diff --git a/core/java/android/app/Notification.java b/core/java/android/app/Notification.java
index 0dd9c63..bcdf3f4 100644
--- a/core/java/android/app/Notification.java
+++ b/core/java/android/app/Notification.java
@@ -1761,7 +1761,9 @@
         if (this.actions != null) {
             that.actions = new Action[this.actions.length];
             for(int i=0; i<this.actions.length; i++) {
-                that.actions[i] = this.actions[i].clone();
+                if ( this.actions[i] != null) {
+                    that.actions[i] = this.actions[i].clone();
+                }
             }
         }
 
@@ -3108,7 +3110,9 @@
          * @param action The action to add.
          */
         public Builder addAction(Action action) {
-            mActions.add(action);
+            if (action != null) {
+                mActions.add(action);
+            }
             return this;
         }
 
@@ -3122,7 +3126,9 @@
         public Builder setActions(Action... actions) {
             mActions.clear();
             for (int i = 0; i < actions.length; i++) {
-                mActions.add(actions[i]);
+                if (actions[i] != null) {
+                    mActions.add(actions[i]);
+                }
             }
             return this;
         }