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

ios/chrome/browser/ui/omnibox/omnibox_text_field_ios_unittest.mm

 // Copyright 2012 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 "ios/chrome/browser/ui/omnibox/omnibox_text_field_ios.h"
 
 #include "base/command_line.h"
 #include "base/files/file_path.h"
 #include "base/files/file_util.h"
-#include "base/mac/scoped_nsobject.h"
 #include "base/path_service.h"
 #include "base/strings/string_split.h"
 #include "base/strings/sys_string_conversions.h"
 #include "ios/chrome/browser/chrome_paths.h"
 #include "ios/chrome/grit/ios_strings.h"
 #include "testing/gtest_mac.h"
 #include "testing/platform_test.h"
 #include "ui/base/l10n/l10n_util_mac.h"
 
+#if !defined(__has_feature) || !__has_feature(objc_arc)
+#error "This file requires ARC support."
+#endif
+
 // A category for making existing methods visible for use in these tests.
 @interface OmniboxTextFieldIOS (VisibleForTesting)
 - (CGRect)rectForDrawTextInRect:(CGRect)rect;
 @end
 
 namespace {
 
 class OmniboxTextFieldIOSTest : public PlatformTest {
  protected:
   void SetUp() override {
     PlatformTest::SetUp();
     // This rect is fairly arbitrary. The text field just needs a non-zero width
     // so that the pre-edit label's text alignment can be tested.
     CGRect rect = CGRectMake(0, 0, 100, 20);
-    textfield_.reset([[OmniboxTextFieldIOS alloc] initWithFrame:rect]);
+    textfield_ = [[OmniboxTextFieldIOS alloc] initWithFrame:rect];
     [[[UIApplication sharedApplication] keyWindow] addSubview:textfield_];
   };
 
   void TearDown() override { [textfield_ removeFromSuperview]; }
 
   BOOL IsCopyUrlInMenu() {
     UIMenuController* menuController = [UIMenuController sharedMenuController];
     NSString* const kTitle = l10n_util::GetNSString(IDS_IOS_COPY_URL);
     for (UIMenuItem* item in menuController.menuItems) {
       if ([item.title isEqual:kTitle])
@@ skipping 64 matching lines @@
       // Increment |i| and |start| for the next iteration of the outer while
       // loop.  This also requires |j| to be reset.
       ++i;
       j = i + 1;
       start = [textfield_ positionFromPosition:beginning offset:i];
     }
 
     [textfield_ resignFirstResponder];
   }
 
-  base::scoped_nsobject<OmniboxTextFieldIOS> textfield_;
+  OmniboxTextFieldIOS* textfield_;
 };
 
 TEST_F(OmniboxTextFieldIOSTest, BecomeFirstResponderAddsCopyURLMenuItem) {
   // The 'Copy URL' menu item should not be present before this test runs.
   EXPECT_FALSE(IsCopyUrlInMenu());
 
   // Call |becomeFirstResponder| and verify the Copy URL menu item was added.
   UIMenuController* menuController = [UIMenuController sharedMenuController];
   NSUInteger expectedItems = [menuController.menuItems count] + 1;
   [textfield_ becomeFirstResponder];
@@ skipping 135 matching lines @@
 }
 
 TEST_F(OmniboxTextFieldIOSTest, SelectAllExitsPreEditState) {
   [textfield_ enterPreEditState];
   EXPECT_TRUE([textfield_ isPreEditing]);
   [textfield_ selectAll:nil];
   EXPECT_FALSE([textfield_ isPreEditing]);
 }
 
 }  // namespace