--- a/dom/media/webvtt/vtt.jsm
+++ b/dom/media/webvtt/vtt.jsm
@@ -399,17 +399,17 @@ Cu.import('resource://gre/modules/Servic
           if (tagStack.length &&
               tagStack[tagStack.length - 1] === t.substr(2).replace(">", "")) {
             tagStack.pop();
             current = current.parentNode;
           }
           // Otherwise just ignore the end tag.
           continue;
         }
-        var ts = collectTimeStamp(t.substr(1, t.length - 2));
+        var ts = collectTimeStamp(t.substr(1, t.length - 1));
         var node;
         if (ts) {
           // Timestamps are lead nodes as well.
           node = window.document.createProcessingInstruction("timestamp", normalizedTimeStamp(ts));
           current.appendChild(node);
           continue;
         }
         var m = t.match(/^<([^.\s/0-9>]+)(\.[^\s\\>]+)?([^>\\]+)?(\\?)>?$/);

deleted file mode 100644
--- a/testing/web-platform/meta/webvtt/parsing/cue-text-parsing/tests/entities.html.ini
+++ /dev/null
@@ -1,23 +0,0 @@
-[entities.html]
-  type: testharness
-  disabled: https://bugzilla.mozilla.org/show_bug.cgi?id=1307710
-  expected:
-    if not debug and e10s and (os == "linux") and (version == "Ubuntu 16.04") and (processor == "x86_64") and (bits == 64): TIMEOUT
-    if debug and not e10s and (os == "linux") and (version == "Ubuntu 16.04") and (processor == "x86") and (bits == 32): CRASH
-    if not debug and e10s and (os == "linux") and (version == "Ubuntu 16.04") and (processor == "x86") and (bits == 32): TIMEOUT
-    if not debug and e10s and (os == "mac") and (version == "OS X 10.10.5") and (processor == "x86_64") and (bits == 64): TIMEOUT
-    if not debug and not e10s and (os == "linux") and (version == "Ubuntu 16.04") and (processor == "x86_64") and (bits == 64): CRASH
-    if not debug and e10s and (os == "win") and (version == "6.1.7601") and (processor == "x86") and (bits == 32): TIMEOUT
-    if debug and e10s and (os == "linux") and (version == "Ubuntu 16.04") and (processor == "x86_64") and (bits == 64): TIMEOUT
-    if debug and not e10s and (os == "win") and (version == "6.1.7601") and (processor == "x86") and (bits == 32): CRASH
-    if not debug and not e10s and (os == "linux") and (version == "Ubuntu 16.04") and (processor == "x86") and (bits == 32): CRASH
-    if not debug and not e10s and (os == "win") and (version == "6.1.7601") and (processor == "x86") and (bits == 32): CRASH
-    if debug and e10s and (os == "mac") and (version == "OS X 10.10.5") and (processor == "x86_64") and (bits == 64): TIMEOUT
-    if not debug and not e10s and (os == "win") and (version == "6.2.9200") and (processor == "x86_64") and (bits == 64): CRASH
-    if not debug and not e10s and (os == "mac") and (version == "OS X 10.10.5") and (processor == "x86_64") and (bits == 64): CRASH
-    if debug and e10s and (os == "win") and (version == "6.2.9200") and (processor == "x86_64") and (bits == 64): TIMEOUT
-    if debug and e10s and (os == "linux") and (version == "Ubuntu 16.04") and (processor == "x86") and (bits == 32): TIMEOUT
-    if not debug and e10s and (os == "win") and (version == "6.2.9200") and (processor == "x86_64") and (bits == 64): TIMEOUT
-    if debug and e10s and (os == "win") and (version == "6.1.7601") and (processor == "x86") and (bits == 32): TIMEOUT
-    if debug and not e10s and (os == "win") and (version == "6.2.9200") and (processor == "x86_64") and (bits == 64): CRASH
-    if debug and not e10s and (os == "linux") and (version == "Ubuntu 16.04") and (processor == "x86_64") and (bits == 64): CRASH

deleted file mode 100644
--- a/testing/web-platform/meta/webvtt/parsing/cue-text-parsing/tests/tags.html.ini
+++ /dev/null
@@ -1,23 +0,0 @@
-[tags.html]
-  type: testharness
-  disabled: https://bugzilla.mozilla.org/show_bug.cgi?id=1307710
-  expected:
-    if not debug and e10s and (os == "linux") and (version == "Ubuntu 16.04") and (processor == "x86_64") and (bits == 64): TIMEOUT
-    if debug and not e10s and (os == "linux") and (version == "Ubuntu 16.04") and (processor == "x86") and (bits == 32): CRASH
-    if not debug and e10s and (os == "linux") and (version == "Ubuntu 16.04") and (processor == "x86") and (bits == 32): TIMEOUT
-    if not debug and e10s and (os == "mac") and (version == "OS X 10.10.5") and (processor == "x86_64") and (bits == 64): TIMEOUT
-    if not debug and not e10s and (os == "linux") and (version == "Ubuntu 16.04") and (processor == "x86_64") and (bits == 64): CRASH
-    if not debug and e10s and (os == "win") and (version == "6.1.7601") and (processor == "x86") and (bits == 32): TIMEOUT
-    if debug and e10s and (os == "linux") and (version == "Ubuntu 16.04") and (processor == "x86_64") and (bits == 64): TIMEOUT
-    if debug and not e10s and (os == "win") and (version == "6.1.7601") and (processor == "x86") and (bits == 32): CRASH
-    if not debug and not e10s and (os == "linux") and (version == "Ubuntu 16.04") and (processor == "x86") and (bits == 32): CRASH
-    if not debug and not e10s and (os == "win") and (version == "6.1.7601") and (processor == "x86") and (bits == 32): CRASH
-    if debug and e10s and (os == "mac") and (version == "OS X 10.10.5") and (processor == "x86_64") and (bits == 64): TIMEOUT
-    if not debug and not e10s and (os == "win") and (version == "6.2.9200") and (processor == "x86_64") and (bits == 64): CRASH
-    if not debug and not e10s and (os == "mac") and (version == "OS X 10.10.5") and (processor == "x86_64") and (bits == 64): CRASH
-    if debug and e10s and (os == "win") and (version == "6.2.9200") and (processor == "x86_64") and (bits == 64): TIMEOUT
-    if debug and e10s and (os == "linux") and (version == "Ubuntu 16.04") and (processor == "x86") and (bits == 32): TIMEOUT
-    if not debug and e10s and (os == "win") and (version == "6.2.9200") and (processor == "x86_64") and (bits == 64): TIMEOUT
-    if debug and e10s and (os == "win") and (version == "6.1.7601") and (processor == "x86") and (bits == 32): TIMEOUT
-    if debug and not e10s and (os == "win") and (version == "6.2.9200") and (processor == "x86_64") and (bits == 64): CRASH
-    if debug and not e10s and (os == "linux") and (version == "Ubuntu 16.04") and (processor == "x86_64") and (bits == 64): CRASH

deleted file mode 100644
--- a/testing/web-platform/meta/webvtt/parsing/cue-text-parsing/tests/timestamps.html.ini
+++ /dev/null
@@ -1,8 +0,0 @@
-[timestamps.html]
-  type: testharness
-  [WebVTT cue data parser test timestamps - 47fa4306a695161da88533d456ce94829e53b13d]
-    expected: FAIL
-
-  [WebVTT cue data parser test timestamps - c1036a4322c1852e02e5a1843a9a81dfca6d7af3]
-    expected: FAIL
-