Milo Refactor: Remove theme support

milo/common/miloerror/error.go

Index: milo/common/miloerror/error.go
diff --git a/milo/common/miloerror/error.go b/milo/common/miloerror/error.go
deleted file mode 100644
index b1c90224ad300a229d507e928b5b6d2d633cb26c..0000000000000000000000000000000000000000
--- a/milo/common/miloerror/error.go
+++ /dev/null
@@ -1,19 +0,0 @@
-// Copyright 2015 The LUCI Authors. All rights reserved.
-// Use of this source code is governed under the Apache License, Version 2.0
-// that can be found in the LICENSE file.
-
-package miloerror
-
-import (
-	"fmt"
-)
-
-// Error is used for all milo errors.
-type Error struct {
-	Message string
-	Code    int
-}
-
-func (e Error) Error() string {
-	return fmt.Sprintf("encountered error %d, %s", e.Code, e.Message)
-}