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

client/dom/generated/src/frog/Float32Array.dart

 
-class Float32ArrayJs extends ArrayBufferViewJs implements Float32Array, List<num> native "*Float32Array" {
+class _Float32ArrayJs extends _ArrayBufferViewJs implements Float32Array, List<num> native "*Float32Array" {
 
   factory Float32Array(int length) =>  _construct_Float32Array(length);
 
   factory Float32Array.fromList(List<num> list) => _construct_Float32Array(list);
 
   factory Float32Array.fromBuffer(ArrayBuffer buffer) => _construct_Float32Array(buffer);
 
   static _construct_Float32Array(arg) native 'return new Float32Array(arg);';
 
   static final int BYTES_PER_ELEMENT = 4;
@@ skipping 66 matching lines @@
   void insertRange(int start, int length, [num initialValue]) {
     throw new UnsupportedOperationException("Cannot insertRange on immutable List.");
   }
   List<num> getRange(int start, int length) =>
       _Lists.getRange(this, start, length, <num>[]);
 
   // -- end List<num> mixins.
 
   void setElements(Object array, [int offset = null]) native;
 
-  Float32ArrayJs subarray(int start, [int end = null]) native;
+  _Float32ArrayJs subarray(int start, [int end = null]) native;
 }