Add rendering context and rendering 2D context to OffscreenCanvas

third_party/WebKit/Source/modules/offscreencanvas/OffscreenCanvasRenderingContextFactory.h

+// Copyright (c) 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.
+
+#ifndef OffscreenCanvasRenderingContextFactory_h
+#define OffscreenCanvasRenderingContextFactory_h
+
+#include "wtf/Allocator.h"
+#include "wtf/PassRefPtr.h"
+
+namespace blink {
+
+class CanvasContextCreationAttributes;
+class OffscreenCanvas;
+class OffscreenCanvasRenderingContext;
+
+class OffscreenCanvasRenderingContextFactory {
+    USING_FAST_MALLOC(OffscreenCanvasRenderingContextFactory);
+    WTF_MAKE_NONCOPYABLE(OffscreenCanvasRenderingContextFactory);
+public:
+    OffscreenCanvasRenderingContextFactory() = default;
+    virtual ~OffscreenCanvasRenderingContextFactory() { }
+
+    virtual OffscreenCanvasRenderingContext* create(OffscreenCanvas*, const CanvasContextCreationAttributes&) = 0;
+    virtual OffscreenCanvasRenderingContext::ContextType contextType() const = 0;
+    virtual void onError(OffscreenCanvas*, const String& error) = 0;
+};
+
+} // namespace blink
+
+#endif // OffscreenCanvasRenderingContextFactory_h