Add shadow/corner radius to notifications (toasts and in-center).

ui/gfx/shadow_util.h

+// Copyright 2017 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 UI_GFX_SHADOW_UTIL_H_
+#define UI_GFX_SHADOW_UTIL_H_
+
+#include "ui/gfx/gfx_export.h"
+#include "ui/gfx/image/image_skia.h"
+#include "ui/gfx/shadow_value.h"
+
+namespace gfx {
+
+// A struct that describes a vector of shadows and their depiction as an image
+// suitable for ninebox tiling.
+struct GFX_EXPORT ShadowDetails {
+  ShadowDetails();
+  ShadowDetails(const ShadowDetails& other);
+  ~ShadowDetails();
+
+  // Returns a cached ShadowDetails for the given elevation (which controls
+  // style) and corner radius. Creates the ShadowDetails first if necessary.
+  static const ShadowDetails& Get(int elevation, int radius);
+
+  // Description of the shadows.
+  gfx::ShadowValues values;
+  // Cached ninebox image based on |values|.
+  gfx::ImageSkia ninebox_image;
+};
+
+}  // namespace gfx
+
+#endif  // UI_GFX_SHADOW_UTIL_H_