Warn about overriding operator== but not hashCode.

dart/tests/compiler/dart2js/analyze_api_test.dart

Index: dart/tests/compiler/dart2js/analyze_api_test.dart
diff --git a/dart/tests/compiler/dart2js/analyze_api_test.dart b/dart/tests/compiler/dart2js/analyze_api_test.dart
index 5c6da035ea74bd7a1d0623216d7980de79f98866..da23e8f12147bd4cd521ec71f605dbaaf6a8e347 100644
--- a/dart/tests/compiler/dart2js/analyze_api_test.dart
+++ b/dart/tests/compiler/dart2js/analyze_api_test.dart
@@ -23,6 +23,14 @@ const Map<String, List<String>> WHITE_LIST = const {
   'path_observer.dart':
       const ['Warning: Using "new Symbol"', // Issue 10565.
             ],
+  'sdk/lib/html/dart2js/html_dart2js.dart':
+      const ['Warning: The class "Rect" overrides "operator==", '
+             'but not "get hashCode".',
+             'Warning: The class "Point" overrides "operator==", '
+             'but not "get hashCode".',
+             'Warning: The class "_ClientRect" overrides "operator==", '
+             'but not "get hashCode".',
+      ],
 };
 
 void main() {