Extracting more than one wallpaper prominent color

components/wallpaper/wallpaper_color_extraction_result.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 COMPONENTS_WALLPAPER_WALLPAPER_COLOR_EXTRACTION_RESULT_H_
+#define COMPONENTS_WALLPAPER_WALLPAPER_COLOR_EXTRACTION_RESULT_H_
+
+namespace wallpaper {
+
+// This enum is used to back a histogram, and should therefore be treated as
+// append-only.
+enum WallpaperColorExtractionResult {

[xdai1, 2017/06/21 16:29:30]

I think we prefer enum class?

[Qiang(Joe) Xu, 2017/06/21 22:35:27]

We might still need enum.
base::Bucket in the test needs integer parameter:
https://cs.chromium.org/chromium/src/base/test/histogram_tester.h?type=cs&q=b...

+  // Transparent result on (dark, vibrant) color profile.
+  RESULT_DARK_VIBRANT_TRANSPARENT = 0,
+  // Opaque result on (dark, vibrant) color profile.
+  RESULT_DARK_VIBRANT_OPAQUE,
+  // Transparent result on (normal, vibrant) color profile.
+  RESULT_NORMAL_VIBRANT_TRANSPARENT,
+  // Opaque result on (normal, vibrant) color profile.
+  RESULT_NORMAL_VIBRANT_OPAQUE,
+  // Transparent result on (light, vibrant) color profile.
+  RESULT_LIGHT_VIBRANT_TRANSPARENT,
+  // Opaque result on (light, vibrant) color profile.
+  RESULT_LIGHT_VIBRANT_OPAQUE,
+  // Transparent result on (dark, muted) color profile.
+  RESULT_DARK_MUTED_TRANSPARENT,
+  // Opaque result on (dark, muted) color profile.
+  RESULT_DARK_MUTED_OPAQUE,
+  // Transparent result on (normal, muted) color profile.
+  RESULT_NORMAL_MUTED_TRANSPARENT,
+  // Opaque result on (normal, muted) color profile.
+  RESULT_NORMAL_MUTED_OPAQUE,
+  // Transparent result on (light, muted) color profile.
+  RESULT_LIGHT_MUTED_TRANSPARENT,
+  // Opaque result on (light, muted) color profile.
+  RESULT_LIGHT_MUTED_OPAQUE,
+
+  NUM_COLOR_EXTRACTION_RESULTS,
+};
+
+}  // namespace wallpaper
+
+#endif  // COMPONENTS_WALLPAPER_WALLPAPER_COLOR_EXTRACTION_RESULT_H_