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

third_party/WebKit/Source/modules/canvas/HTMLCanvasElementModule.cpp

+// Copyright 2016 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "modules/canvas/HTMLCanvasElementModule.h"
+
+#include "core/html/canvas/CanvasContextCreationAttributes.h"
+#include "core/html/canvas/CanvasRenderingContext.h"
+
+namespace blink {
+
+void HTMLCanvasElementModule::getContext(HTMLCanvasElement& canvas, const String& type, const CanvasContextCreationAttributes& attributes, RenderingContext& result)
+{
+    CanvasRenderingContext* context = canvas.getCanvasRenderingContext(type, attributes);
+    if (context) {
+        context->setCanvasGetContextResult(result);
+    }
+}
+
+}