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

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

 
-class FileWriterJs extends DOMTypeJs implements FileWriter native "*FileWriter" {
+class _FileWriterJs extends _DOMTypeJs implements FileWriter native "*FileWriter" {
 
   static final int DONE = 2;
 
   static final int INIT = 0;
 
   static final int WRITING = 1;
 
-  FileErrorJs get error() native "return this.error;";
+  _FileErrorJs get error() native "return this.error;";
 
   int get length() native "return this.length;";
 
   EventListener get onabort() native "return this.onabort;";
 
   void set onabort(EventListener value) native "this.onabort = value;";
 
   EventListener get onerror() native "return this.onerror;";
 
   void set onerror(EventListener value) native "this.onerror = value;";
@@ skipping 17 matching lines @@
   int get position() native "return this.position;";
 
   int get readyState() native "return this.readyState;";
 
   void abort() native;
 
   void seek(int position) native;
 
   void truncate(int size) native;
 
-  void write(BlobJs data) native;
+  void write(_BlobJs data) native;
 }