Add Matrix4x3 and tristimulus class to color utiliies.

ui/gfx/color_utils.h

Index: ui/gfx/color_utils.h
diff --git a/ui/gfx/color_utils.h b/ui/gfx/color_utils.h
index fc8b44652869e4d8c678aff83420c0db416f8f4e..4abe087f8f5d3ca5581059a81f3276ccaa4e61a1 100644
--- a/ui/gfx/color_utils.h
+++ b/ui/gfx/color_utils.h
@@ -12,6 +12,42 @@ 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;