Gtk3 ui: Add libgtk3ui as a separate build component

chrome/browser/ui/libgtk2ui/skia_utils_gtk2.h

-// Copyright (c) 2012 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 CHROME_BROWSER_UI_LIBGTK2UI_SKIA_UTILS_GTK2_H_
-#define CHROME_BROWSER_UI_LIBGTK2UI_SKIA_UTILS_GTK2_H_
-
-#include <stdint.h>
-
-#include "third_party/skia/include/core/SkColor.h"
-
-typedef struct _GdkColor GdkColor;
-typedef struct _GdkPixbuf GdkPixbuf;
-
-class SkBitmap;
-
-// Define a macro for creating GdkColors from RGB values.  This is a macro to
-// allow static construction of literals, etc.  Use this like:
-//   GdkColor white = GDK_COLOR_RGB(0xff, 0xff, 0xff);
-#define GDK_COLOR_RGB(r, g, b) {0, r * ::libgtk2ui::kSkiaToGDKMultiplier,  \
-        g * ::libgtk2ui::kSkiaToGDKMultiplier,                          \
-        b * ::libgtk2ui::kSkiaToGDKMultiplier}
-
-namespace libgtk2ui {
-
-// Multiply uint8_t color components by this.
-const int kSkiaToGDKMultiplier = 257;
-
-// Converts GdkColors to the ARGB layout Skia expects.
-SkColor GdkColorToSkColor(GdkColor color);
-
-// Converts ARGB to GdkColor.
-GdkColor SkColorToGdkColor(SkColor color);
-
-const SkBitmap GdkPixbufToImageSkia(GdkPixbuf* pixbuf);
-
-// Convert and copy a SkBitmap to a GdkPixbuf. NOTE: this uses BGRAToRGBA, so
-// it is an expensive operation.  The returned GdkPixbuf will have a refcount of
-// 1, and the caller is responsible for unrefing it when done.
-GdkPixbuf* GdkPixbufFromSkBitmap(const SkBitmap& bitmap);
-
-}  // namespace libgtk2ui
-
-#endif  // CHROME_BROWSER_UI_LIBGTK2UI_SKIA_UTILS_GTK2_H_