[ObjC ARC] Converts ios/chrome/browser/ui/toolbar:toolbar to ARC.

ios/chrome/browser/ui/toolbar/BUILD.gn

Index: ios/chrome/browser/ui/toolbar/BUILD.gn
diff --git a/ios/chrome/browser/ui/toolbar/BUILD.gn b/ios/chrome/browser/ui/toolbar/BUILD.gn
index 014ae540ab9492a2a300147bcda1705c81c41334..32b6c41f6d8b0ffc700ea151fca937fa79f364c0 100644
--- a/ios/chrome/browser/ui/toolbar/BUILD.gn
+++ b/ios/chrome/browser/ui/toolbar/BUILD.gn
@@ -38,6 +38,7 @@ bundle_data("resources") {
 }
 
 source_set("toolbar") {
+  configs += [ "//build/config/compiler:enable_arc" ]
   sources = [
     "new_tab_button.h",
     "new_tab_button.mm",
@@ -90,6 +91,7 @@ source_set("toolbar") {
     "//ios/chrome/browser/ui/fancy_ui",
     "//ios/chrome/browser/ui/history",
     "//ios/chrome/browser/ui/keyboard",
+    "//ios/chrome/browser/ui/popup_menu",
     "//ios/chrome/browser/ui/qr_scanner",
     "//ios/chrome/browser/ui/tools_menu",
     "//ios/chrome/browser/ui/util",