Use a union typdef for the return type of canvas.getContext

third_party/WebKit/Source/core/html/HTMLCanvasElement.idl

 /*
  * Copyright (C) 2006, 2008, 2009 Apple Inc. All rights reserved.
  * Copyright (C) 2010 Torch Mobile (Beijing) Co. Ltd. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
@@ skipping 10 matching lines @@
  * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
  * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
 // https://html.spec.whatwg.org/#the-canvas-element
 
 interface HTMLCanvasElement : HTMLElement
 {
+    // Note: Due to dependecies on modules, getContext is defined in a partial
+    // interface in HTMLCanvasElementModule.idl
+
     // FIXME: width and height should be unsigned long.
     attribute long width;
     attribute long height;
 
-    // Note: this differs deliberately from the specified Web IDL for this function:
-    //     RenderingContext? getContext(DOMString contextId, any... arguments);
-    // in order to eliminate the custom binding. It is functionally equivalent.
-    //
-    // The PermissiveDictionaryConversion extended attribute is needed to allow the
-    // autogenerated code to match the behavior of the custom binding. Web IDL
-    // requires throwing TypeError if the incoming argument is not an object type
-    // (and is not undefined or null). The binding must ignore this.
-    //
-    // Also note: the only reason this must return type "any" is to allow the
-    // InspectorInstrumentation wrappers to be called for canvases. If that could be
-    // handled differently the return type could be changed to "RenderingContext?"
-    // and the [CallWith=ScriptState] extended attribute removed.
-    //
-    [CallWith=ScriptState] any getContext(DOMString contextId, [PermissiveDictionaryConversion] optional CanvasContextCreationAttributes attributes);
-
     // Note: The arguments argument is variadic in the spec, but not here as
     // only one extra argument is actually used.
     // FIXME: type should not have a default value.
     [RaisesException] DOMString toDataURL(optional DOMString type = null, optional any arguments);
 
     [RaisesException] void toBlob(BlobCallback _callback, optional DOMString type = null, optional any arguments);
 };