Make dart:dom implementation types private so they don't muddle the docs.

client/dom/generated/src/frog/CSSStyleDeclaration.dart

Index: client/dom/generated/src/frog/CSSStyleDeclaration.dart
diff --git a/client/dom/generated/src/frog/CSSStyleDeclaration.dart b/client/dom/generated/src/frog/CSSStyleDeclaration.dart
index 9997f804d7c804f930ddcf0aade0d27df419c442..735b7fd63dad9646894c3e38d7e3f0eff6acf730 100644
--- a/client/dom/generated/src/frog/CSSStyleDeclaration.dart
+++ b/client/dom/generated/src/frog/CSSStyleDeclaration.dart
@@ -1,5 +1,5 @@
 
-class CSSStyleDeclarationJs extends DOMTypeJs implements CSSStyleDeclaration native "*CSSStyleDeclaration" {
+class _CSSStyleDeclarationJs extends _DOMTypeJs implements CSSStyleDeclaration native "*CSSStyleDeclaration" {
 
   String get cssText() native "return this.cssText;";
 
@@ -7,9 +7,9 @@ class CSSStyleDeclarationJs extends DOMTypeJs implements CSSStyleDeclaration nat
 
   int get length() native "return this.length;";
 
-  CSSRuleJs get parentRule() native "return this.parentRule;";
+  _CSSRuleJs get parentRule() native "return this.parentRule;";
 
-  CSSValueJs getPropertyCSSValue(String propertyName) native;
+  _CSSValueJs getPropertyCSSValue(String propertyName) native;
 
   String getPropertyPriority(String propertyName) native;