Removed INVALID_XML_SPACE error.

The implementation of DOMParser on Internet Explorer and Edge actually
implement xml:space, which means that if you passed in an invalid value
the parser would error immediately.
Thus, on IE and Edge, an invalid xml:space value would return an
INVALID_XML error instead of an INVALID_XML_SPACE error.
Though clear errors are useful, such browser-dependent behavior would
just be confusing in the long run.

Change-Id: I46c24452a216fa8bc242148e23d275230f277037

lib/media/ttml_text_parser.js

@@ -78,7 +78,7 @@ shaka.media.TtmlTextParser =
     if (spaceStyle != 'default' && spaceStyle != 'preserve') {
       throw new shaka.util.Error(
           shaka.util.Error.Category.TEXT,
-          shaka.util.Error.Code.INVALID_XML_SPACE);
+          shaka.util.Error.Code.INVALID_XML);
     }
     var whitespaceTrim = spaceStyle == 'default';
 

lib/util/error.js

@@ -233,11 +233,6 @@ shaka.util.Error.Code = {
    */
   'INVALID_MP4_VTT': 2008,
 
-  /** The text parser failed to parse a text stream due to an invalid
-    * xml:space value.
-    */
-  'INVALID_XML_SPACE': 2009,
-
 
   /**
    * Some component tried to read past the end of a buffer.  The segment index,

test/media/ttml_text_parser_unit.js

@@ -69,7 +69,7 @@ describe('TtmlTextParser', function() {
         ],
         '<tt>' + ttBody + '</tt>');
     // Any other value is rejected as an error.
-    errorHelper(shaka.util.Error.Code.INVALID_XML_SPACE,
+    errorHelper(shaka.util.Error.Code.INVALID_XML,
                 '<tt xml:space="invalid">' + ttBody + '</tt>');
   });