LibGfx: Remove unused alpha premultiplication functions

Author: tcl3

Libraries/LibGfx/Color.h

@@ -316,28 +316,6 @@ class Color {
         return color_with_alpha;
     }
 
-    constexpr Color to_premultiplied() const
-    {
-        u32 a = alpha();
-        u8 r = static_cast<u8>((red() * a + 127) / 255);
-        u8 g = static_cast<u8>((green() * a + 127) / 255);
-        u8 b = static_cast<u8>((blue() * a + 127) / 255);
-        return Color(r, g, b, a);
-    }
-
-    constexpr Color to_unpremultiplied() const
-    {
-        u32 a = alpha();
-        if (a == 0)
-            return Color(0, 0, 0, 0);
-        if (a == 255)
-            return *this;
-        u8 r = static_cast<u8>(min(255u, (red() * 255u + a / 2) / a));
-        u8 g = static_cast<u8>(min(255u, (green() * 255u + a / 2) / a));
-        u8 b = static_cast<u8>(min(255u, (blue() * 255u + a / 2) / a));
-        return Color(r, g, b, a);
-    }
-
     constexpr Color blend(Color source) const
     {
         if (alpha() == 0 || source.alpha() == 255)