Improve GL bindings for Ganesh surfaces.

mojo/skia/ganesh_framebuffer_surface.h

+// Copyright 2015 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 MOJO_SKIA_GANESH_FRAMEBUFFER_SURFACE_H_
+#define MOJO_SKIA_GANESH_FRAMEBUFFER_SURFACE_H_
+
+#include <memory>
+
+#include "mojo/gpu/gl_texture.h"
+#include "mojo/skia/ganesh_context.h"
+#include "skia/ext/refptr.h"
+#include "third_party/skia/include/core/SkSurface.h"
+
+namespace mojo {
+
+// This class represents an SkSurface backed by a GL framebuffer, which is
+// appropriate for use with Ganesh.  This is useful for rendering Skia
+// commands directly to the display framebuffer.
+class GaneshFramebufferSurface {
+ public:
+  // Creates a surface that wraps the currently bound GL framebuffer.
+  // The size of the surface is determined by querying the current viewport.
+  explicit GaneshFramebufferSurface(GaneshContext* context);
+  ~GaneshFramebufferSurface();
+
+  SkSurface* surface() const { return surface_.get(); }
+  SkCanvas* canvas() const { return surface_->getCanvas(); }
+
+ private:
+  skia::RefPtr<SkSurface> surface_;
+
+  DISALLOW_COPY_AND_ASSIGN(GaneshFramebufferSurface);
+};
+
+}  // namespace mojo
+
+#endif  // MOJO_SKIA_GANESH_FRAMEBUFFER_SURFACE_H_