Removed DARTIUM codegen for IDLS (sdk/lib/dartium)

tools/dom/templates/html/impl/impl_WebGL2RenderingContext.darttemplate

 // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 part of $LIBRARYNAME;
 
 @DocsEditable()
 $(ANNOTATIONS)$(NATIVESPEC)class $CLASSNAME$EXTENDS implements _WebGL2RenderingContextBase, _WebGLRenderingContextBase {
 $!MEMBERS
 
   @DomName('WebGLRenderingContext2.readPixels')
   @DocsEditable()
   void readPixels(int x, int y, int width, int height, int format, int type,
           TypedData pixels) {
-$if DART2JS
       _readPixels(x, y, width, height, format, type, pixels);
-$else
-      var data = js.toArrayBufferView(pixels);
-      _readPixels(x, y, width, height, format, type, data);
-      for (var i = 0; i < data.length; i++) {
-        pixels[i] = data[i];
-      }
-$endif
   }
 }