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

ios/chrome/browser/ui/toolbar/toolbar_model_impl_ios_unittest.mm

Index: ios/chrome/browser/ui/toolbar/toolbar_model_impl_ios_unittest.mm
diff --git a/ios/chrome/browser/ui/toolbar/toolbar_model_impl_ios_unittest.mm b/ios/chrome/browser/ui/toolbar/toolbar_model_impl_ios_unittest.mm
index 80eddcb1c91a0e7f2e30715a5e84fe3e442b0853..b29b25e889c35f7ca72d291856f38f4c08c89254 100644
--- a/ios/chrome/browser/ui/toolbar/toolbar_model_impl_ios_unittest.mm
+++ b/ios/chrome/browser/ui/toolbar/toolbar_model_impl_ios_unittest.mm
@@ -6,7 +6,6 @@
 
 #include <memory>
 
-#include "base/mac/scoped_nsobject.h"
 #include "base/memory/ptr_util.h"
 #include "base/message_loop/message_loop.h"
 #include "base/strings/utf_string_conversions.h"
@@ -31,6 +30,10 @@
 #include "third_party/ocmock/gtest_support.h"
 #include "third_party/ocmock/ocmock_extensions.h"
 
+#if !defined(__has_feature) || !__has_feature(objc_arc)
+#error "This file requires ARC support."
+#endif
+
 namespace {
 
 static const char kWebUrl[] = "http://www.chromium.org";
@@ -39,6 +42,7 @@ static const char kNativeUrl[] = "chrome://version";
 class ToolbarModelImplIOSTest : public PlatformTest {
  protected:
   void SetUp() override {
+    PlatformTest::SetUp();
     TestChromeBrowserState::Builder test_cbs_builder;
     chrome_browser_state_ = test_cbs_builder.Build();
     chrome_browser_state_->CreateBookmarkModel(true);