1985 no longer supports webkitBackingStorePixelRatio on CanvasRenderingContext2D

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 77 matching lines @@
 [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;
+
+  // Removed in 1985.
+  [Suppressed] readonly attribute float webkitBackingStorePixelRatio; 
 };
 
 [Supplemental]
 interface ConsoleBase {
   [Suppressed] void assert(boolean condition);
   [CallWith=ScriptArguments|ScriptState] void assertCondition(boolean condition);
 };
 
 interface HTMLCanvasElement {
   [Suppressed] DOMString toDataURL([TreatNullAs=NullString, TreatUndefinedAs=NullString,Default=Undefined] DOMString type);
@@ skipping 261 matching lines @@
 [Suppressed]
 interface Promise {};
 
 [Supplemental]
 interface Screen {
     [Suppressed]
     boolean lockOrientation(sequence<DOMString> orientations);
 };
 
 Element implements GlobalEventHandlers;