Make dart:dom implementation types private so they don't muddle the docs.

client/dom/generated/src/frog/Int16Array.dart

 
-class Int16ArrayJs extends ArrayBufferViewJs implements Int16Array, List<int> native "*Int16Array" {
+class _Int16ArrayJs extends _ArrayBufferViewJs implements Int16Array, List<int> native "*Int16Array" {
 
   factory Int16Array(int length) =>  _construct_Int16Array(length);
 
   factory Int16Array.fromList(List<int> list) => _construct_Int16Array(list);
 
   factory Int16Array.fromBuffer(ArrayBuffer buffer) => _construct_Int16Array(buffer);
 
   static _construct_Int16Array(arg) native 'return new Int16Array(arg);';
 
   static final int BYTES_PER_ELEMENT = 2;
@@ skipping 66 matching lines @@
   void insertRange(int start, int length, [int initialValue]) {
     throw new UnsupportedOperationException("Cannot insertRange on immutable List.");
   }
   List<int> getRange(int start, int length) =>
       _Lists.getRange(this, start, length, <int>[]);
 
   // -- end List<int> mixins.
 
   void setElements(Object array, [int offset = null]) native;
 
-  Int16ArrayJs subarray(int start, [int end = null]) native;
+  _Int16ArrayJs subarray(int start, [int end = null]) native;
 }