[vr] Migrate from vr::Colorf to SkColor

device/vr/vr_types.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 DEVICE_VR_VR_TYPES_H_
 #define DEVICE_VR_VR_TYPES_H_
 
 #include <array>
 
 #include "ui/gfx/geometry/point3_f.h"
 #include "ui/gfx/geometry/point_f.h"
 #include "ui/gfx/geometry/rect.h"
 #include "ui/gfx/geometry/rect_f.h"
 #include "ui/gfx/geometry/size.h"
 #include "ui/gfx/geometry/vector3d_f.h"
 
 namespace vr {
 
 using Mat4f = std::array<std::array<float, 4>, 4>;
 
 typedef struct RotationAxisAngle {
   float x;
   float y;
   float z;
   float angle;
 } RotationAxisAngle;
 
-typedef struct Colorf {
-  float r;
-  float g;
-  float b;
-  float a;
-} Colorf;
-
 // A floating point quaternion, in JPL format.
 typedef struct Quatf {
   /// qx, qy, qz are the vector component.
   float qx;
   float qy;
   float qz;
   /// qw is the linear component.
   float qw;
 } Quatf;
 
 }  // namespace vr
 
 #endif  // DEVICE_VR_VR_TYPES_H_