refactor(gioui): move common iconbutton code to a function

tracker/gioui/buttons.go

@@ -0,0 +1,20 @@
+package gioui
+
+import (
+	"gioui.org/layout"
+	"gioui.org/unit"
+	"gioui.org/widget"
+	"gioui.org/widget/material"
+)
+
+func IconButton(th *material.Theme, w *widget.Clickable, icon []byte, enabled bool) material.IconButtonStyle {
+	ret := material.IconButton(th, w, widgetForIcon(icon))
+	ret.Background = transparent
+	ret.Inset = layout.UniformInset(unit.Dp(6))
+	if enabled {
+		ret.Color = primaryColor
+	} else {
+		ret.Color = disabledTextColor
+	}
+	return ret
+}