Improve Ganesh helpers.

mojo/skia/ganesh_helpers.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_HELPERS_H_
+#define MOJO_SKIA_GANESH_HELPERS_H_
+
+#include "base/callback.h"
+#include "mojo/skia/ganesh_context.h"
+#include "skia/ext/refptr.h"
+
+class SkImage;
+
+namespace mojo {
+namespace skia {
+
+// Creates a Skia image from a GL texture.
+// The underlying texture must be kept alive for as long as the SkImage exists.
+// Invokes |release_callback| when the SkImage is deleted.
+::skia::RefPtr<SkImage> CreateImageFromTexture(
+    GaneshContext* context,
+    uint32_t texture_id,
+    uint32_t width,
+    uint32_t height,
+    const base::Closure& release_callback);
+
+}  // namespace skia
+}  // namespace mojo
+
+#endif  // MOJO_SKIA_GANESH_HELPERS_H_