Fix detection of CDMA cell broadcast messages.

The bIsServicePresent field of an incoming CDMA SMS RIL message
is not a reliable way to distinguish broadcast from point-to-point
messages on some RILs. Change CDMA SmsMessage.getMessageType() to
return MESSAGE_TYPE_BROADCAST when the service category is not 0,
and MESSAGE_TYPE_POINT_TO_POINT when the service category is 0.

Bug: 6853691
Change-Id: I0d44a8ce0bb295da5125271db90652570d655bc1

Author: Jake Hamby

telephony/java/com/android/internal/telephony/cdma/SmsMessage.java

@@ -468,7 +468,13 @@ public static TextEncodingDetails calculateLength(CharSequence messageBody,
      *  {@link com.android.internal.telephony.cdma.sms.SmsEnvelope#MESSAGE_TYPE_ACKNOWLEDGE},
     */
     /* package */ int getMessageType() {
-        return mEnvelope.messageType;
+        // NOTE: mEnvelope.messageType is not set correctly for cell broadcasts with some RILs.
+        // Use the service category parameter to detect CMAS and other cell broadcast messages.
+        if (mEnvelope.serviceCategory != 0) {
+            return SmsEnvelope.MESSAGE_TYPE_BROADCAST;
+        } else {
+            return SmsEnvelope.MESSAGE_TYPE_POINT_TO_POINT;
+        }
     }
 
     /**