Introduce SVGPaintServer

Source/core/paint/SVGPaintServer.h

+// Copyright 2014 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 SVGPaintServer_h
+#define SVGPaintServer_h
+
+#include "core/rendering/svg/RenderSVGResource.h"
+#include "platform/graphics/Gradient.h"
+#include "platform/graphics/Pattern.h"
+
+namespace blink {
+
+class GraphicsContext;
+class GraphicsContextStateSaver;
+
+class SVGPaintServer {
+public:
+    explicit SVGPaintServer(Color);
+    explicit SVGPaintServer(PassRefPtr<Gradient>);
+    explicit SVGPaintServer(PassRefPtr<Pattern>);
+
+    static SVGPaintServer invalid() { return SVGPaintServer(Color::transparent); }
+
+    // Update the GC state (on |stateSaver.context()|) for painting |renderer|
+    // using |style|. |resourceModeFlags| is used to decide between fill/stroke.
+    // Previous state will be saved (if needed) using |stateSaver|.
+    static bool updateGraphicsContext(GraphicsContextStateSaver&, RenderStyle*, RenderObject&, RenderSVGResourceModeFlags);
+
+    void apply(GraphicsContext&, RenderSVGResourceMode, GraphicsContextStateSaver* = 0);
+
+    bool isValid() const { return m_color != Color::transparent; }
+
+private:
+    static SVGPaintServer requestForRenderer(RenderObject&, RenderStyle*, RenderSVGResourceModeFlags);
+
+    RefPtr<Gradient> m_gradient;
+    RefPtr<Pattern> m_pattern;
+    Color m_color;
+};
+
+} // namespace blink
+
+#endif // SVGPaintServer_h