Fix all dartanalyzer errors in dart:sky except the Native ones.

sky/engine/core/dom/Range.idl

 /*
  * Copyright (C) 2006 Apple Computer, Inc.
  * Copyright (C) 2006 Samuel Weinig <sam.weinig@gmail.com>
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
  *
  * This library is distributed in the hope that it will be useful,
@@ skipping 29 matching lines @@
     void collapse(optional boolean toStart = false);
     [RaisesException] void selectNode(Node refNode);
     [RaisesException] void selectNodeContents(Node refNode);
 
     // CompareHow
     const unsigned short START_TO_START = 0;
     const unsigned short START_TO_END   = 1;
     const unsigned short END_TO_END     = 2;
     const unsigned short END_TO_START   = 3;
 
-    [RaisesException, TypeChecking=Interface] short compareBoundaryPoints(CompareHow how, Range sourceRange);
+    // TODO(eseidel): Generate a dart enum for above.
+    // [RaisesException, TypeChecking=Interface] short compareBoundaryPoints(CompareHow how, Range sourceRange);
 
     [RaisesException, CustomElementCallbacks] void deleteContents();
     [RaisesException, CustomElementCallbacks] DocumentFragment extractContents();
     [RaisesException, CustomElementCallbacks] DocumentFragment cloneContents();
     [RaisesException, CustomElementCallbacks] void insertNode(Node newNode);
     [RaisesException, CustomElementCallbacks] void surroundContents(Node newParent);
     Range cloneRange();
 
     stringifier;
 
@@ skipping 12 matching lines @@
     // CompareResults
     const unsigned short NODE_BEFORE           = 0;
     const unsigned short NODE_AFTER            = 1;
     const unsigned short NODE_BEFORE_AND_AFTER = 2;
     const unsigned short NODE_INSIDE           = 3;
 
     [RaisesException] short compareNode([Default=Undefined] optional Node refNode);
 
     [RaisesException] void expand([Default=Undefined] optional DOMString unit);
 };