color: Add support for shader generation

ui/gfx/color_transform.h

Index: ui/gfx/color_transform.h
diff --git a/ui/gfx/color_transform.h b/ui/gfx/color_transform.h
index 5368b7a6a7bb956cc0ae6fed292b1b5cf09e2975..c72ebe96b42a53598fdb1537d27539d34010b03c 100644
--- a/ui/gfx/color_transform.h
+++ b/ui/gfx/color_transform.h
@@ -26,6 +26,14 @@ class GFX_EXPORT ColorTransform {
   // Perform transformation of colors, |colors| is both input and output.
   virtual void Transform(TriStim* colors, size_t num) = 0;
 
+  // Return GLSL shader source that defines a function DoColorConversion that
+  // converts a vec3 according to this transform.
+  virtual bool CanGetShaderSource() const = 0;
+  virtual std::string GetShaderSource() const = 0;
+
+  // Returns true if this transform is the identity.
+  virtual bool IsIdentity() const = 0;
+
   virtual size_t NumberOfStepsForTesting() const = 0;
 
   static std::unique_ptr<ColorTransform> NewColorTransform(