Add missing null checks on Conference and Connection.

Also add missing bundle passing for Connection Events.

Bug: 27850430
Change-Id: I0f79635929cbe5da18b528b6c1119c7ce4d8e32b
diff --git a/telecomm/java/android/telecom/Conference.java b/telecomm/java/android/telecom/Conference.java
index 00e07af..f5c4eb1 100644
--- a/telecomm/java/android/telecom/Conference.java
+++ b/telecomm/java/android/telecom/Conference.java
@@ -665,7 +665,7 @@
         if (mPreviousExtraKeys != null) {
             List<String> toRemove = new ArrayList<String>();
             for (String oldKey : mPreviousExtraKeys) {
-                if (!extras.containsKey(oldKey)) {
+                if (extras == null || !extras.containsKey(oldKey)) {
                     toRemove.add(oldKey);
                 }
             }
@@ -681,7 +681,9 @@
             mPreviousExtraKeys = new ArraySet<String>();
         }
         mPreviousExtraKeys.clear();
-        mPreviousExtraKeys.addAll(extras.keySet());
+        if (extras != null) {
+            mPreviousExtraKeys.addAll(extras.keySet());
+        }
     }
 
     /**