Add LINEAR_HDR so that the linear scRGB colorspace will be HDR

ui/gfx/color_space.h

 // Copyright (c) 2012 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 UI_GFX_COLOR_SPACE_H_
 #define UI_GFX_COLOR_SPACE_H_
 
 #include <stdint.h>
 
 #include "base/gtest_prod_util.h"
@@ skipping 72 matching lines @@
     UNKNOWN = 1000,
     GAMMA24,
 
     // This is an ad-hoc transfer function that decodes SMPTE 2084 content
     // into a 0-1 range more or less suitable for viewing on a non-hdr
     // display.
     SMPTEST2084_NON_HDR,
 
     // TODO(hubbe): Need to store an approximation of the gamma function(s).
     CUSTOM,
+    // Like LINEAR, but intended for HDR. (can go outside of 0-1)
+    LINEAR_HDR,
     LAST = CUSTOM,
   };
 
   enum class MatrixID : int16_t {
     // The first 0-255 values should match the H264 specification (see Table E-5
     // Matrix Coefficients in https://www.itu.int/rec/T-REC-H.264/en).
     RGB = 0,
     BT709 = 1,
     UNSPECIFIED = 2,
     RESERVED = 3,
@@ skipping 85 matching lines @@
   friend class ICCProfile;
   friend class ColorSpaceToColorSpaceTransform;
   friend class ColorSpaceWin;
   friend struct IPC::ParamTraits<gfx::ColorSpace>;
   FRIEND_TEST_ALL_PREFIXES(SimpleColorSpace, GetColorSpace);
 };
 
 }  // namespace gfx
 
 #endif  // UI_GFX_COLOR_SPACE_H_