Reland of [WebRTC] A real ScreenCapturer test

webrtc/modules/desktop_capture/rgba_color.h

Index: webrtc/modules/desktop_capture/rgba_color.h
diff --git a/webrtc/modules/desktop_capture/rgba_color.h b/webrtc/modules/desktop_capture/rgba_color.h
new file mode 100644
index 0000000000000000000000000000000000000000..ff4a2584152d720e6ecd0fa0bfd50dfa819ac9d1
--- /dev/null
+++ b/webrtc/modules/desktop_capture/rgba_color.h
@@ -0,0 +1,54 @@
+/*
+ *  Copyright (c) 2016 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#ifndef WEBRTC_MODULES_DESKTOP_CAPTURE_RGBA_COLOR_H_
+#define WEBRTC_MODULES_DESKTOP_CAPTURE_RGBA_COLOR_H_
+
+#include <stdint.h>
+
+#include "webrtc/modules/desktop_capture/desktop_frame.h"
+
+namespace webrtc {
+
+// A four-byte structure to store a color in BGRA format. This structure also
+// provides functions to be created from uint8_t array, say,
+// DesktopFrame::data(). It always uses BGRA order for internal storage to match
+// DesktopFrame::data().
+//
+// This struct is for testing purpose only, and should not be used in production
+// logic.
+struct RgbaColor final {
+  // Creates a color with BGRA channels.
+  RgbaColor(uint8_t blue, uint8_t green, uint8_t red, uint8_t alpha);
+
+  // Creates a color with BGR channels, and set alpha channel to 255 (opaque).
+  RgbaColor(uint8_t blue, uint8_t green, uint8_t red);
+
+  // Creates a color from four-byte in BGRA order, i.e. DesktopFrame::data().
+  explicit RgbaColor(const uint8_t* bgra);
+
+  // Returns true if |this| and |right| is the same color.
+  bool operator==(const RgbaColor& right) const;
+
+  // Returns true if |this| and |right| are different colors.
+  bool operator!=(const RgbaColor& right) const;
+
+  uint8_t blue;
+  uint8_t green;
+  uint8_t red;
+  uint8_t alpha;
+};
+static_assert(
+    DesktopFrame::kBytesPerPixel == sizeof(RgbaColor),
+    "A pixel in DesktopFrame should be safe to be represented by a RgbaColor");
+
+}  // namespace webrtc
+
+#endif  // WEBRTC_MODULES_DESKTOP_CAPTURE_RGBA_COLOR_H_