Move shared constants to //components/chrome_cleaner

components/chrome_cleaner/public/constants/BUILD.gn

Index: components/chrome_cleaner/public/constants/BUILD.gn
diff --git a/components/chrome_cleaner/public/constants/BUILD.gn b/components/chrome_cleaner/public/constants/BUILD.gn
new file mode 100644
index 0000000000000000000000000000000000000000..826ffa6c8792e48164940ef20fa89af77c08a771
--- /dev/null
+++ b/components/chrome_cleaner/public/constants/BUILD.gn
@@ -0,0 +1,10 @@
+# Copyright 2017 The Chromium Authors. All Rights Reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+source_set("constants") {
+  sources = [
+    "constants.cc",
+    "constants.h",
+  ]
+}