Add Matrix4x3 and tristimulus class to color utiliies.

ui/gfx/color_utils.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_UTILS_H_
 #define UI_GFX_COLOR_UTILS_H_
 
 #include "third_party/skia/include/core/SkColor.h"
 #include "ui/gfx/gfx_export.h"
 
 class SkBitmap;
 
 namespace color_utils {
 
+// Tristimulus value, RGB, XYZ,, HSV, YUV, etc.
+struct GFX_EXPORT TriStim {
+  TriStim() {
+    values[0] = 0.0f;
+    values[1] = 0.0f;
+    values[2] = 0.0f;
+  }
+  TriStim(float a, float b, float c) {
+    values[0] = a;
+    values[1] = b;
+    values[2] = c;
+  }
+  float values[3];
+};
+
+// The fourth row is always 0,0,0,1
+struct GFX_EXPORT Matrix4x3 {
+  // Defaults to unity matrix.
+  Matrix4x3();
+
+  // Matrix multiplication.
+  Matrix4x3 operator*(const Matrix4x3& other) const;
+
+  // Color mapping.
+  TriStim operator*(const TriStim& color) const;
+
+  // Invert matrix.
+  Matrix4x3 Invert() const;
+
+  // Lookup, makes it look like the fourth row is there.
+  float lookup(int row, int col) const;
+
+  typedef float Quad[4];
+  Quad rows[3];
+};
+
 // Represents an HSL color.
 struct HSL {
   double h;
   double s;
   double l;
 };
 
 // The minimum contrast between text and background that is still readable.
 // This value is taken from w3c accessibility guidelines.
 const double kMinimumReadableContrastRatio = 4.5f;
@@ skipping 104 matching lines @@
 // light-on-dark color scheme.
 GFX_EXPORT bool IsInvertedColorScheme();
 
 // Derives a color for icons on a UI surface based on the text color on the same
 // surface.
 GFX_EXPORT SkColor DeriveDefaultIconColor(SkColor text_color);
 
 }  // namespace color_utils
 
 #endif  // UI_GFX_COLOR_UTILS_H_