Add rendering context and rendering 2D context to OffscreenCanvas

third_party/WebKit/Source/modules/canvas2d/OffscreenCanvasRenderingContext2D.idl

Index: third_party/WebKit/Source/modules/canvas2d/OffscreenCanvasRenderingContext2D.idl
diff --git a/third_party/WebKit/Source/modules/imagebitmap/ImageBitmapRenderingContext.idl b/third_party/WebKit/Source/modules/canvas2d/OffscreenCanvasRenderingContext2D.idl
similarity index 54%
copy from third_party/WebKit/Source/modules/imagebitmap/ImageBitmapRenderingContext.idl
copy to third_party/WebKit/Source/modules/canvas2d/OffscreenCanvasRenderingContext2D.idl
index ac6f794a3cbc2519847870de0ee1f43e30a3e946..77fe410f1c0d1bb8dbc2db46440b9f64844bbc0c 100644
--- a/third_party/WebKit/Source/modules/imagebitmap/ImageBitmapRenderingContext.idl
+++ b/third_party/WebKit/Source/modules/canvas2d/OffscreenCanvasRenderingContext2D.idl
@@ -2,13 +2,14 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
+// TODO: Propose OffscreenCanvasRenderingContext2D to WHATWG spec 

[Justin Novosad, 2016/03/02 15:41:50]

Instead of this comment put a link to the unofficial spec, with a note that
official spec is WIP.

+
 [
-    RuntimeEnabled=ExperimentalCanvasFeatures,
-    SetWrapperReferenceFrom=canvas,
     WillBeGarbageCollected,
-] interface ImageBitmapRenderingContext {
+    RuntimeEnabled=ExperimentalCanvasFeatures,
+] interface OffscreenCanvasRenderingContext2D {
     // back-reference to the canvas
-    readonly attribute HTMLCanvasElement canvas;
-
-    void transferImageBitmap(ImageBitmap bitmap);
+    readonly attribute OffscreenCanvas offscreenCanvas;
 };
+
+OffscreenCanvasRenderingContext2D implements CanvasPathMethods;