Merge pull request #465 from webcomponents/fix-safari-webgl

Fix safari 9 webgl wrappers

Author: dfreedm

src/ShadowDOM/wrappers.js

@@ -431,6 +431,7 @@ window.ShadowDOMPolyfill = {};
     });
   }
 
+  scope.addForwardingProperties = addForwardingProperties;
   scope.assert = assert;
   scope.constructorTable = constructorTable;
   scope.defineGetter = defineGetter;

src/ShadowDOM/wrappers/WebGLRenderingContext.js

@@ -11,6 +11,7 @@
 (function(scope) {
   'use strict';
 
+  var addForwardingProperties = scope.addForwardingProperties;
   var mixin = scope.mixin;
   var registerWrapper = scope.registerWrapper;
   var setWrapper = scope.setWrapper;
@@ -44,6 +45,15 @@
     }
   });
 
+  // WebKit has two additional prototypes in the chain for WebGLRenderingContext which are not exposed on `window`: WebGLRenderingContextBase and CanvasRenderingContextBase.
+  // CanvasRenderingContextBase has only one getter `canvas`, which is taken care of already, so we skip it.
+
+  var OriginalWebGLRenderingContextBase = Object.getPrototypeOf(OriginalWebGLRenderingContext.prototype);
+
+  if (OriginalWebGLRenderingContextBase !== Object.prototype) {
+    addForwardingProperties(OriginalWebGLRenderingContextBase, WebGLRenderingContext.prototype);
+  }
+
   // Blink/WebKit has broken DOM bindings. Usually we would create an instance
   // of the object and pass it into registerWrapper as a "blueprint" but
   // creating WebGL contexts is expensive and might fail so we use a dummy

tests/ShadowDOM/js/HTMLCanvasElement.js

@@ -113,6 +113,7 @@ suite('HTMLCanvasElement', function() {
     try {
       gl = canvas.getContext('webgl');
     } catch (ex) {
+      console.error(ex);
     }
     // IE10 does not have WebGL.
     // Chrome returns null if the graphics card is not supported