Add DesktopFrame rotation functions

webrtc/modules/desktop_capture/rgba_color.h

 /*
  *  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);
 
   // Creates a color from BGRA channels in a uint format. Consumers should make
   // sure the memory order of the uint32_t is always BGRA from left to right, no
   // matter the system endian. This function creates an equivalent RgbaColor
   // instance from the ToUInt32() result of another RgbaColor instance.
   explicit RgbaColor(uint32_t bgra);
 
+  // Converts an int to uint32_t, and creates a RGBA instance. This constructor
+  // helps users to write RgbaColor(0) without ambiguous conversion error.
+  explicit RgbaColor(int 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;
 
   uint32_t ToUInt32() 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_