image: make AlphaColor.Set conform to usual signature

R=nigeltao, r
CC=golang-dev
https://golang.org/cl/4471045

diff --git a/src/pkg/image/image.go b/src/pkg/image/image.go
index 222d21adefde3caeeb82744c7122b0f0cfc805a1..4350acc82036f2a5cbd7591926ffe3377a0b512a 100644 (file)
--- a/src/pkg/image/image.go
+++ b/src/pkg/image/image.go
@@ -280,7 +280,7 @@ func (p *Alpha) At(x, y int) Color {
        return p.Pix[y*p.Stride+x]
 }
 
-func (p *Alpha) Set(x, y int, c AlphaColor) {
+func (p *Alpha) Set(x, y int, c Color) {
        if !p.Rect.Contains(Point{x, y}) {
                return
        }