text: convert clip.Ops to op.CallOp

MacroOp is about to lose the ability to run a different operation list
than the one it was recorded on. Text shape caches rely on that property,
and must use the new CallOp operation added for purpose.

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

widget/editor.go

@@ -15,7 +15,6 @@ import (
 	"gioui.org/io/pointer"
 	"gioui.org/layout"
 	"gioui.org/op"
-	"gioui.org/op/clip"
 	"gioui.org/op/paint"
 	"gioui.org/text"
 	"gioui.org/unit"
@@ -81,7 +80,7 @@ type SubmitEvent struct {
 
 type line struct {
 	offset f32.Point
-	clip   clip.Op
+	clip   op.CallOp
 }
 
 const (