Componentize TestToolbarModel

components/toolbar/BUILD.gn

 # Copyright 2015 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("toolbar") {
   sources = [
     "toolbar_model.cc",
     "toolbar_model.h",
   ]
 
   deps = [
     "//base",
     "//components/security_state",
     "//url",
   ]
 }
+
+source_set("test_support") {
+  testonly = true
+
+  sources = [
+    "test_toolbar_model.cc",
+    "test_toolbar_model.h",
+  ]
+
+  deps = [
+    ":toolbar",
+    "//base",
+    "//components/resources",
+    "//ui/gfx",
+  ]
+}