Merge "Revert "Use TelephonyManager#isEmergencyNumber() instead"" am: a281046577

Original change: https://android-review.googlesource.com/c/platform/external/ims/+/1702032

Change-Id: Ibb3c11c7bef069dcde89920259e14bac75b70bca
diff --git a/rcs/rcsmanager/src/java/com/android/ims/internal/ContactNumberUtils.java b/rcs/rcsmanager/src/java/com/android/ims/internal/ContactNumberUtils.java
index 094afb4..1ed03f9 100644
--- a/rcs/rcsmanager/src/java/com/android/ims/internal/ContactNumberUtils.java
+++ b/rcs/rcsmanager/src/java/com/android/ims/internal/ContactNumberUtils.java
@@ -134,9 +134,7 @@
     public static int NUMBER_INVALID = 5;
 
     /**
-     * Check if it is a valid contact number for presence.
-     *
-     * Note: mContext must be set via setContext() before calling this method.
+     * Check if it is a valid contact number for presence
      *
      * @param phoneNumber read from contact db.
      * @return contact number error code.
@@ -163,16 +161,7 @@
             return NUMBER_INVALID;
         }
 
-        boolean isEmergencyNumber;
-        if (mContext == null) {
-            Log.e(TAG, "context is unexpectedly null to provide emergency identification service");
-            isEmergencyNumber = false;
-        } else {
-            TelephonyManager tm = mContext.getSystemService(TelephonyManager.class);
-            isEmergencyNumber = tm.isEmergencyNumber(number);
-        }
-
-        if (isEmergencyNumber) {
+        if (PhoneNumberUtils.isEmergencyNumber(number)) {
             return NUMBER_EMERGENCY;
         // TODO: To handle short code
         //} else if ((mContext != null) && PhoneNumberUtils.isN11Number(mContext, number)) {