Start cleaning up the HTML tests.

pkg/dev_compiler/test/not_yet_strong_tests.dart

Index: pkg/dev_compiler/test/not_yet_strong_tests.dart
diff --git a/pkg/dev_compiler/test/not_yet_strong_tests.dart b/pkg/dev_compiler/test/not_yet_strong_tests.dart
index b2d6970269639d2d60a49bc7dbfbc9350e0c21fe..7886944b18bd1b62fc18407ea4f3a3aa1617533b 100644
--- a/pkg/dev_compiler/test/not_yet_strong_tests.dart
+++ b/pkg/dev_compiler/test/not_yet_strong_tests.dart
@@ -2427,30 +2427,12 @@ final notYetStrongTests = new HashSet<String>.from([
   'lib/convert/chunked_conversion_utf8_test',
   'lib/convert/line_splitter_test',
   'lib/html/cross_frame_test',
-  'lib/html/css_rule_list_test',
-  'lib/html/custom/constructor_calls_created_synchronously_test',
-  'lib/html/custom/created_callback_test',
-  'lib/html/custom/document_register_basic_test',
-  'lib/html/custom/document_register_type_extensions_test',
-  'lib/html/custom/element_upgrade_test',
-  'lib/html/custom_elements_23127_test',
-  'lib/html/custom_elements_test',
-  'lib/html/datalistelement_test',
-  'lib/html/documentfragment_test',
-  'lib/html/element_add_test',
-  'lib/html/element_classes_test',
   'lib/html/element_test',
   'lib/html/events_test',
   'lib/html/fileapi_test',
   'lib/html/filereader_test',
   'lib/html/fontface_loaded_test',
-  'lib/html/htmlcollection_test',
-  'lib/html/htmlelement_test',
-  'lib/html/htmloptionscollection_test',
-  'lib/html/indexeddb_2_test',
   'lib/html/js_function_getter_trust_types_test',
-  'lib/html/js_test',
-  'lib/html/js_util_test',
   'lib/html/js_typed_interop_side_cast_exp_test',
   'lib/html/js_typed_interop_side_cast_test',
   'lib/html/keyboard_event_test',