Remove generated directories with 100s of files.

client/html/generated/html/dartium/MutationEvent.dart

Index: client/html/generated/html/dartium/MutationEvent.dart
diff --git a/client/html/generated/html/dartium/MutationEvent.dart b/client/html/generated/html/dartium/MutationEvent.dart
deleted file mode 100644
index 93d8d6ecdb64dd146ed57fa9770ba1b2a10c9cf2..0000000000000000000000000000000000000000
--- a/client/html/generated/html/dartium/MutationEvent.dart
+++ /dev/null
@@ -1,19 +0,0 @@
-
-class _MutationEventImpl extends _EventImpl implements MutationEvent {
-  _MutationEventImpl._wrap(ptr) : super._wrap(ptr);
-
-  int get attrChange() => _wrap(_ptr.attrChange);
-
-  String get attrName() => _wrap(_ptr.attrName);
-
-  String get newValue() => _wrap(_ptr.newValue);
-
-  String get prevValue() => _wrap(_ptr.prevValue);
-
-  Node get relatedNode() => _wrap(_ptr.relatedNode);
-
-  void initMutationEvent(String type, bool canBubble, bool cancelable, Node relatedNode, String prevValue, String newValue, String attrName, int attrChange) {
-    _ptr.initMutationEvent(_unwrap(type), _unwrap(canBubble), _unwrap(cancelable), _unwrap(relatedNode), _unwrap(prevValue), _unwrap(newValue), _unwrap(attrName), _unwrap(attrChange));
-    return;
-  }
-}