Fix bitmap leaks in InCallUI

Fix the bitmap leaks in InCallUI that were a result of
StatusBarNotifier instances being retained across calls.

Bitmap -> StatusBarNotifier -> CallUpdateListenerMap ->
CallList

Bug: 25003292
Change-Id: I4f8695d7dfbc397b0fee0305a6f94e8d2e8e593f

src/com/android/incallui/StatusBarNotifier.java

diff --git a/src/com/android/incallui/StatusBarNotifier.java b/src/com/android/incallui/StatusBarNotifier.java
index a9b6ccc..4d4e349 100644
--- a/src/com/android/incallui/StatusBarNotifier.java
+++ b/src/com/android/incallui/StatusBarNotifier.java
@@ -118,6 +118,10 @@
      * @see #updateInCallNotification(InCallState,CallList)
      */
     private void cancelNotification() {
+        if (!TextUtils.isEmpty(mCallId)) {
+            CallList.getInstance().removeCallUpdateListener(mCallId, this);
+            mCallId = null;
+        }
         if (mCurrentNotification != NOTIFICATION_NONE) {
             Log.d(this, "cancelInCall()...");
             mNotificationManager.cancel(mCurrentNotification);
@@ -161,7 +165,7 @@
         final boolean isIncoming = (call.getState() == Call.State.INCOMING ||
                 call.getState() == Call.State.CALL_WAITING);
 
-        if (mCallId != null) {
+        if (!TextUtils.isEmpty(mCallId)) {
             CallList.getInstance().removeCallUpdateListener(mCallId, this);
         }
         mCallId = call.getId();