Make the reader types more permissive of inputs.

Now the EbmlParser and DataViewReader types can accept BufferSource
objects to avoid the caller having to convert it at each callsite.

Change-Id: I527fbc638485214bfe976d7da89b79b6098033a8

lib/util/buffer_utils.js

@@ -22,7 +22,7 @@ goog.require('shaka.util.Iterables');
 
 /**
  * @summary A set of BufferSource utility functions.
- * @exportDoc
+ * @exportInterface
  */
 shaka.util.BufferUtils = class {
   /**