Implement PaintWorkletGlobalScope#registerPaint() for the CSS Paint API

third_party/WebKit/Source/modules/csspaint/CSSPaintDefinition.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 CSSPaintDefinition_h
+#define CSSPaintDefinition_h
+
+#include "bindings/core/v8/ScopedPersistent.h"
+#include "platform/geometry/IntSize.h"
+#include "platform/heap/Handle.h"
+#include <v8.h>
+
+namespace blink {
+
+class ScriptState;
+
+class CSSPaintDefinition final : public RefCountedWillBeGarbageCollectedFinalized<CSSPaintDefinition> {
+public:
+    static PassRefPtrWillBeRawPtr<CSSPaintDefinition> create(ScriptState*, v8::Local<v8::Function> constructor, v8::Local<v8::Function> paint);
+    virtual ~CSSPaintDefinition();
+
+    v8::Local<v8::Function> paintFunctionForTesting(v8::Isolate* isolate) { return m_paint.newLocal(isolate); }
+
+    DEFINE_INLINE_TRACE() { };
+
+private:
+    CSSPaintDefinition(ScriptState*, v8::Local<v8::Function> constructor, v8::Local<v8::Function> paint);
+
+    RefPtr<ScriptState> m_scriptState;
+
+    ScopedPersistent<v8::Function> m_constructor;
+    ScopedPersistent<v8::Function> m_paint;

[haraken, 2016/03/31 02:01:59]

What's the point of making CSSPaintDefinition hold these weak persistents? What
are they used for?

[ikilpatrick, 2016/03/31 21:59:05]

This is the next patch in the pipeline. CSSPaintDefinition will be used for
calling into the paint function to produce an Image.
https://codereview.chromium.org/1834843002/diff/60001/third_party/WebKit/Sour...

I was following CustomElements naming here, might be a better name?

+};
+
+} // namespace blink
+
+#endif // CSSPaintDefinition_h