Bug 1550185 - Ensure GeckoView CrashHandler.getRootException() does not return null r=snorp

Differential Revision: https://phabricator.services.mozilla.com/D30422

--HG--
extra : moz-landing-system : lando

mobile/android/geckoview/src/main/java/org/mozilla/gecko/CrashHandler.java

@@ -56,10 +56,12 @@ public class CrashHandler implements Thread.UncaughtExceptionHandler {
      */
     public static Throwable getRootException(final Throwable exc) {
         Throwable cause;
+        Throwable result = exc;
         for (cause = exc; cause != null; cause = cause.getCause()) {
+          result = cause;
         }
 
-        return cause;
+        return result;
     }
 
     /**