[ios clean] Adds ToolsMenu to Showcase.

ios/showcase/tools_menu/BUILD.gn

Index: ios/showcase/tools_menu/BUILD.gn
diff --git a/ios/showcase/tools_menu/BUILD.gn b/ios/showcase/tools_menu/BUILD.gn
new file mode 100644
index 0000000000000000000000000000000000000000..6ab5355378189595b4698f478b714ed6a52f2a25
--- /dev/null
+++ b/ios/showcase/tools_menu/BUILD.gn
@@ -0,0 +1,19 @@
+# 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("tools_menu") {
+  sources = [
+    "sc_tools_coordinator.h",
+    "sc_tools_coordinator.mm",
+  ]
+  deps = [
+    "//base",
+    "//ios/clean/chrome/browser/ui/commands",
+    "//ios/clean/chrome/browser/ui/tools:tools_ui",
+    "//ios/showcase/common",
+    "//ui/base",
+  ]
+  libs = [ "UIKit.framework" ]
+  configs += [ "//build/config/compiler:enable_arc" ]
+}