Adds an iOS implementation of gfx::Image.

ui/gfx/image/image_skia_util_ios.mm

+// Copyright 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.
+
+#include "ui/gfx/image/image_skia_util_ios.h"
+
+#include <UIKit/UIKit.h>
+
+#include "base/logging.h"
+#include "skia/ext/skia_utils_ios.h"
+#include "third_party/skia/include/core/SkBitmap.h"
+#include "ui/gfx/image/image_skia.h"
+
+namespace gfx {
+
+gfx::ImageSkia ImageSkiaFromUIImage(UIImage* image) {
+  gfx::ImageSkia image_skia;
+  if (!image)
+    return image_skia;
+
+  // iOS only supports one scale factor.
+  std::vector<ui::ScaleFactor> supported_scale_factors =
+      ui::GetSupportedScaleFactors();
+  DCHECK_EQ(1U, supported_scale_factors.size());
+  if (supported_scale_factors.size() < 1)
+    return image_skia;
+
+  ui::ScaleFactor scale_factor = supported_scale_factors[0];
+  float scale = ui::GetScaleFactorScale(scale_factor);
+  CGSize size = image.size;
+  CGSize desired_size_for_scale =
+      CGSizeMake(size.width * scale, size.height * scale);
+  SkBitmap bitmap(gfx::UIImageToSkBitmap(image, desired_size_for_scale, false));
+  if (!bitmap.isNull())
+    image_skia.AddRepresentation(gfx::ImageSkiaRep(bitmap, scale_factor));
+  return image_skia;
+}
+
+UIImage* UIImageFromImageSkia(const gfx::ImageSkia& image_skia) {
+  if (image_skia.isNull())
+    return nil;
+
+  // iOS only supports one scale factor.
+  std::vector<ui::ScaleFactor> supported_scale_factors =
+      ui::GetSupportedScaleFactors();
+  DCHECK_EQ(1U, supported_scale_factors.size());
+  if (supported_scale_factors.size() < 1)
+    return nil;
+
+  image_skia.EnsureRepsForSupportedScaleFactors();
+  const ImageSkiaRep& rep =
+      image_skia.GetRepresentation(supported_scale_factors[0]);
+  return gfx::SkBitmapToUIImage(rep.sk_bitmap());
+}
+
+}  // namespace gfx