Bug 846769 - Allow up to five assertions in test_seek.html.

content/media/test/test_seek.html

@@ -31,7 +31,7 @@ if (navigator.platform.startsWith("Win")) {
 } else {
   // This is "###!!! ASSERTION: Page read cursor should be inside range: 'mPageOffset <= endOffset'"
   // https://bugzilla.mozilla.org/show_bug.cgi?id=846769
-  SimpleTest.expectAssertions(0, 1);
+  SimpleTest.expectAssertions(0, 5);
 }
 
 const NUM_SEEK_TESTS = 13;