Convert //ios from scoped_ptr to std::unique_ptr.

ios/web/navigation/navigation_item_impl_unittest.mm

Index: ios/web/navigation/navigation_item_impl_unittest.mm
diff --git a/ios/web/navigation/navigation_item_impl_unittest.mm b/ios/web/navigation/navigation_item_impl_unittest.mm
index 0189ea04c3a9be95a75a02c36ce1d1bcdb151e65..e978e2f149aeb5e60967aaeb3c226bae8c9daac7 100644
--- a/ios/web/navigation/navigation_item_impl_unittest.mm
+++ b/ios/web/navigation/navigation_item_impl_unittest.mm
@@ -2,11 +2,13 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
+#include "ios/web/navigation/navigation_item_impl.h"
+
+#include <memory>
+
 #include "base/logging.h"
 #include "base/mac/scoped_nsobject.h"
-#include "base/memory/scoped_ptr.h"
 #include "base/strings/sys_string_conversions.h"
-#include "ios/web/navigation/navigation_item_impl.h"
 #include "testing/gtest/include/gtest/gtest.h"
 #include "testing/gtest_mac.h"
 #include "testing/platform_test.h"
@@ -31,7 +33,7 @@ class NavigationItemTest : public PlatformTest {
   }
 
   // The NavigationItemImpl instance being tested.
-  scoped_ptr<NavigationItemImpl> item_;
+  std::unique_ptr<NavigationItemImpl> item_;
 };
 
 // TODO(rohitrao): Add and adapt tests from NavigationEntryImpl.