Revert "Creating a common library for all DOM types."

sdk/lib/html/src/_Collections.dart

Index: sdk/lib/html/src/_Collections.dart
diff --git a/sdk/lib/html/html_common/collections.dart b/sdk/lib/html/src/_Collections.dart
similarity index 97%
rename from sdk/lib/html/html_common/collections.dart
rename to sdk/lib/html/src/_Collections.dart
index 7202899f7643263135fc8e4f7111343084075cd9..4bd77cd8e3453b32da11a7760c09f5a4cf8698ff 100644
--- a/sdk/lib/html/html_common/collections.dart
+++ b/sdk/lib/html/src/_Collections.dart
@@ -2,14 +2,14 @@
 // 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 html_common;
+part of html;
 
 /**
  * The [Collections] class implements static methods useful when
  * writing a class that implements [Collection] and the [iterator]
  * method.
  */
-class Collections {
+class _Collections {
   static bool contains(Iterable<Object> iterable, Object element) {
     for (final e in iterable) {
       if (e == element) return true;