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.
  */
 
@@ skipping 22 matching lines @@
 
   // 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);

[Sergey Ulanov, 2016/11/17 02:07:39]

Do you still need this?

[Hzj_jie, 2016/11/17 07:14:55]

Yes, it uses in test_utils_unittest.cc.

+
   // 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_