app/internal/srgb: move sRGB emulation to new internal package

Signed-off-by: Elias Naur <mail@eliasnaur.com>

app/headless/headless_js.go

@@ -7,12 +7,11 @@ import (
 	"syscall/js"
 
 	"gioui.org/app/internal/glimpl"
-	"gioui.org/gpu/gl"
 )
 
 type jsContext struct {
 	ctx js.Value
-	f   gl.Functions
+	f   *glimpl.Functions
 }
 
 func newContext() (*jsContext, error) {
@@ -38,7 +37,7 @@ func newContext() (*jsContext, error) {
 	return c, nil
 }
 
-func (c *jsContext) Functions() gl.Functions {
+func (c *jsContext) Functions() *glimpl.Functions {
 	return c.f
 }