Bug 1540580 - Add crashtest for WebM with 0 sized samples. r=jya

Depends on D25846

Differential Revision: https://phabricator.services.mozilla.com/D25847

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

dom/media/test/crashtests/crashtests.list

@@ -118,5 +118,6 @@ test-pref(media.navigator.permission.disabled,true) load 1388372.html
 load 1494073.html
 skip-if(Android) load 1526044.html # Bug 1528391
 load 1533909.html
+load empty-samples.webm # Bug 1540580
 test-pref(media.autoplay.block-webaudio,false) load 1545133.html
 load track-with-zero-dimensions.mp4