Add public_deps for //components/toolbar:test_support and //components/search_engines

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.
 
 import("//build/config/ui.gni")
 import("//ui/vector_icons/vector_icons.gni")
 
 aggregate_vector_icons("toolbar_vector_icons") {
   icon_directory = "vector_icons"
 
@@ skipping 48 matching lines @@
 }
 
 static_library("test_support") {
   testonly = true
 
   sources = [
     "test_toolbar_model.cc",
     "test_toolbar_model.h",
   ]
 
-  deps = [
+  public_deps = [
     ":toolbar",
     "//base",
+  ]
+
+  deps = [
     "//components/resources",
     "//ui/gfx",
   ]
 
   if (toolkit_views) {
     # Needed to get the TOOLKIT_VIEWS define.
     deps += [ "//ui/views" ]
   }
 }