[ash-md] Updated the overflow shelf to change colors based on the wallpaper.

ash/test/wallpaper_controller_test_api.cc

+// 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.
+
+#include "ash/test/wallpaper_controller_test_api.h"
+#include "ash/wallpaper/wallpaper_controller.h"
+#include "ui/gfx/canvas.h"
+#include "ui/gfx/geometry/size.h"
+#include "ui/gfx/image/image_skia.h"
+
+namespace ash {
+namespace test {
+
+WallpaperControllerTestApi::WallpaperControllerTestApi(
+    WallpaperController* controller)
+    : controller_(controller) {}
+
+WallpaperControllerTestApi::~WallpaperControllerTestApi() {}
+
+SkColor WallpaperControllerTestApi::ApplyColorProducingWallpaper() {
+  const SkColor color = SkColorSetRGB(60, 40, 40);
+  const SkColor expected_color = SkColorSetRGB(30, 20, 20);
+
+  gfx::Canvas canvas(gfx::Size(5, 5), 1.0f, true);
+  canvas.DrawColor(color);
+  gfx::ImageSkia image = gfx::ImageSkia::CreateFrom1xBitmap(canvas.GetBitmap());
+  controller_->SetWallpaperImage(image, wallpaper::WALLPAPER_LAYOUT_CENTER);
+
+  return expected_color;
+}
+
+}  // namespace test
+}  // namespace ash