Hook up CSSPaintValue::image to CSS Paint API callback.

third_party/WebKit/Source/core/css/CSSPaintImageGenerator.h

+// 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.
+
+#ifndef CSSPaintImageGenerator_h
+#define CSSPaintImageGenerator_h
+
+#include "core/CoreExport.h"
+#include "platform/geometry/IntSize.h"
+#include "platform/heap/Handle.h"
+
+namespace blink {
+
+class Document;
+class Image;
+
+class CORE_EXPORT CSSPaintImageGenerator : public GarbageCollectedFinalized<CSSPaintImageGenerator> {

[chrishtr, 2016/04/06 18:55:20]

Why do you need both a CSSPaintImageGenerator and CSSPaintImageGeneratorImpl?

[ikilpatrick, 2016/04/07 23:03:00]

Source/core cannot depend on Source/modules. Hence defining the interface in
core, then implementation in modules.
An analogous class is core/html/canvas/CanvasRenderingContext.h &
modules/canvas2d/CanvasRenderingContext2D.h

+public:
+    class Observer {
+    public:
+        virtual ~Observer() { };
+        virtual void paintImageGeneratorReady() = 0;
+    };
+
+    static CSSPaintImageGenerator* create(const String& name, Document&, Observer*);
+    virtual ~CSSPaintImageGenerator();
+
+    typedef CSSPaintImageGenerator* (*CSSPaintImageGeneratorCreateFunction)(const String&, Document&, Observer*);
+    static void init(CSSPaintImageGeneratorCreateFunction);
+
+    virtual PassRefPtr<Image> paint(const IntSize&) = 0;
+
+    DEFINE_INLINE_VIRTUAL_TRACE() { }
+};
+
+} // namespace blink
+
+#endif // CSSPaintImageGenerator_h