Revert 2 CLs to get one last Dartium 34.

tools/dom/idl/dart/dart.idl

 // This file introduces / supplements and forces Dart declarations.
 
 [Supplemental,
  Constructor]
 interface AudioContext {
   // TODO(ager): Auto-generate this custom method when the info about retaining
   // typed arrays is in the IDL.
   [Custom] void decodeAudioData(ArrayBuffer audioData, AudioBufferCallback successCallback, AudioBufferCallback errorCallback);
 };
 
@@ skipping 17 matching lines @@
   CanvasRenderingContext getCSSCanvasContext(DOMString contextId, DOMString name, long width, long height);
   [Custom] Element createElement(DOMString tagName);
   [Custom] Element createElement(DOMString localName, DOMString typeExtension);
   [Custom] Element createElementNS(DOMString namespaceURI, DOMString qualifiedName);
   [Custom] Element createElementNS(DOMString namespaceURI, DOMString qualifiedName, DOMString typeExtension);
 };
 
 [Supplemental]
 interface Node {
   [Custom] Node cloneNode([Default=Undefined] optional boolean deep);
-  [Suppressed] readonly attribute Element nextElementSibling;
-  [Suppressed] readonly attribute Element previousElementSibling;
 };
 
 [Supplemental]
 interface ScriptProcessorNode {
   [Suppressed] attribute EventListener onaudioprocess;
   [Custom] void _setEventListener(EventListener eventListener);
 };
 
 /*
 // TODO(vsm): How should this interact with the new ChildNode and
 // ParentNode interfaces?
 // Force ElementTraversal. WebKit defines these directly.
 interface ElementTraversal : ChildNode, ParentNode {
   readonly attribute unsigned long childElementCount;
   readonly attribute Element firstElementChild;
   readonly attribute Element lastElementChild;
   readonly attribute Element nextElementSibling;
   readonly attribute Element previousElementSibling;
 };
 Element implements ElementTraversal;
 */
 
-[Supplemental]
-interface Element {
-  readonly attribute Element nextElementSibling;
-  readonly attribute Element previousElementSibling;
-};
-
-[Supplemental]
-interface CharacterData {
-  readonly attribute Element nextElementSibling;
-  readonly attribute Element previousElementSibling;
-};
-
 [Callback]
 interface TimeoutHandler {
   void handleEvent();
 };
 
 // FIXME(leafp): This is a temporary hack to get things running while
 // we are still generating _blink from the dart side idl files.
 // Once we are up and running generating dart:_blink in dartium
 // this should go away.
 [Supplemental]
 interface URL {
   [Suppressed] static DOMString createObjectURL(WebKitMediaSource source);
 };
 
 [Supplemental]
 interface CanvasRenderingContext2D {
   [DartName=createImageDataFromImageData] ImageData createImageData(ImageData imagedata);
 
-  // Removed in 1916.
-  [Suppressed] void drawSystemFocusRing(Element element);
-
-  [Suppressed] void assert(boolean condition);
-
   [Suppressed] attribute boolean webkitImageSmoothingEnabled;
 };
 
 [Supplemental]
 interface ConsoleBase {
   [Suppressed] void assert(boolean condition);
   [CallWith=ScriptArguments|ScriptState] void assertCondition(boolean condition);
 };
 
 interface HTMLCanvasElement {
@@ skipping 255 matching lines @@
 
 [Suppressed]
 interface TextDecoder {};
 
 [Supplemental]
 interface Window : EventTarget {};
 
 [Suppressed]
 interface Promise {};
 
-[Supplemental]
-interface Screen {
-    [Suppressed]
-    boolean lockOrientation(sequence<DOMString> orientations);
-};
-
 Element implements GlobalEventHandlers;