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

ios/chrome/browser/ui/ntp/centering_scrollview_unittest.mm

Index: ios/chrome/browser/ui/ntp/centering_scrollview_unittest.mm
diff --git a/ios/chrome/browser/ui/ntp/centering_scrollview_unittest.mm b/ios/chrome/browser/ui/ntp/centering_scrollview_unittest.mm
index d421ecde0ae673f6067bc31fc5b73fd4ad0de553..b78318207202563457250e70610f2f61401557c5 100644
--- a/ios/chrome/browser/ui/ntp/centering_scrollview_unittest.mm
+++ b/ios/chrome/browser/ui/ntp/centering_scrollview_unittest.mm
@@ -2,29 +2,32 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-#include "base/mac/scoped_nsobject.h"
 #import "ios/chrome/browser/ui/ntp/centering_scrollview.h"
 #include "testing/gtest/include/gtest/gtest.h"
 #include "testing/gtest_mac.h"
 #include "testing/platform_test.h"
 
+#if !defined(__has_feature) || !__has_feature(objc_arc)
+#error "This file requires ARC support."
+#endif
+
 namespace {
 
 class CenteringScrollViewTest : public PlatformTest {
  protected:
   void SetUp() override {
-    scrollView_.reset([[CenteringScrollView alloc] initWithFrame:CGRectZero]);
-    contentView_.reset([[UIView alloc] initWithFrame:CGRectZero]);
+    scrollView_ = [[CenteringScrollView alloc] initWithFrame:CGRectZero];
+    contentView_ = [[UIView alloc] initWithFrame:CGRectZero];
   };
 
-  base::scoped_nsobject<CenteringScrollView> scrollView_;
-  base::scoped_nsobject<UIView> contentView_;
+  CenteringScrollView* scrollView_;
+  UIView* contentView_;
 };
 
 TEST_F(CenteringScrollViewTest, CenteringContent) {
   // Set up content view to be smaller than the scrolling view.
   [contentView_ setFrame:CGRectMake(0.0, 0.0, 80.0, 120.0)];
-  [scrollView_ addSubview:contentView_.get()];
+  [scrollView_ addSubview:contentView_];
   // Do test.
   [scrollView_ setFrame:CGRectMake(0.0, 0.0, 320, 480.0)];
   [scrollView_ layoutSubviews];
@@ -42,7 +45,7 @@ TEST_F(CenteringScrollViewTest, CenteringContent) {
 TEST_F(CenteringScrollViewTest, ScrollingContent) {
   // Set up content view taller than the scrolling view.
   [contentView_ setFrame:CGRectMake(0.0, 0.0, 240.0, 400.0)];
-  [scrollView_ addSubview:contentView_.get()];
+  [scrollView_ addSubview:contentView_];
   // Do test
   [scrollView_ setFrame:CGRectMake(0.0, 0.0, 480.0, 320.0)];
   [scrollView_ layoutSubviews];
@@ -60,7 +63,7 @@ TEST_F(CenteringScrollViewTest, ScrollingContent) {
 TEST_F(CenteringScrollViewTest, ResetContentSize) {
   // Set up content view taller than the scrolling view.
   [contentView_ setFrame:CGRectMake(0.0, 0.0, 240.0, 400.0)];
-  [scrollView_ addSubview:contentView_.get()];
+  [scrollView_ addSubview:contentView_];
 
   [scrollView_ setFrame:CGRectMake(0.0, 0.0, 280.0, 440.0)];
   [scrollView_ layoutSubviews];