Bug 1278748 - part2 : correct default value of webidl's property. r=rillian

Line default value : https://w3c.github.io/webvtt/#webvtt-cue-line
Position default value : https://w3c.github.io/webvtt/#webvtt-cue-position

MozReview-Commit-ID: 7S5EXlU2qRF

--HG--
extra : rebase_source : 7f707f054bf3d3481116d2031f8097d4575900fb

testing/web-platform/meta/webvtt/webvtt-file-format-parsing/webvtt-file-parsing/001.html.ini

@@ -1,8 +1,5 @@
 [001.html]
   type: testharness
-  [WebVTT parser tests, settings-vertical.vtt]
-    expected: FAIL
-
   [WebVTT parser tests, settings-position.vtt]
     expected: FAIL
 
@@ -21,9 +18,6 @@
   [WebVTT parser tests, nulls.vtt]
     expected: FAIL
 
-  [WebVTT parser tests, header-garbage.vtt]
-    expected: FAIL
-
   [WebVTT parser tests, header-timings.vtt]
     expected: FAIL
 
@@ -33,9 +27,6 @@
   [WebVTT parser tests, header-tab.vtt]
     expected: FAIL
 
-  [WebVTT parser tests, ids.vtt]
-    expected: FAIL
-
   [WebVTT parser tests, arrows.vtt]
     expected: FAIL
 
@@ -48,15 +39,5 @@
   [WebVTT parser tests, timings-too-long.vtt]
     expected: FAIL
 
-  [WebVTT parser tests, newlines.vtt]
-    expected: FAIL
-
-  [WebVTT parser tests, omitted-hours.vtt]
-    expected: FAIL
-
   [WebVTT parser tests, timings-60.vtt]
-    expected: FAIL
-
-  [WebVTT parser tests, timings-negative.vtt]
-    expected: FAIL
-
+    expected: FAIL

testing/web-platform/tests/webvtt/webvtt-file-format-parsing/webvtt-file-parsing/001.html

@@ -14,8 +14,8 @@ var cueDefaults = {
 "pauseOnExit":false,
 //"vertical":"", (not supported)
 "snapToLines":true,
-"line":-1,
-"position":50,
+"line":"auto",
+"position":"auto",
 "size":100,
 "align":"center"
 }