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

ios/chrome/browser/reading_list/reading_list_model_unittest.cc

 // Copyright 2016 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.
 
 #include "ios/chrome/browser/reading_list/reading_list_model_memory.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 namespace {
 
 class ReadingListModelTest : public ReadingListModelObserver,
@@ skipping 73 matching lines @@
   int observer_loaded_;
   int observer_started_batch_update_;
   int observer_completed_batch_update_;
   int observer_deleted_;
   int observer_remove_unread_;
   int observer_remove_read_;
   int observer_add_unread_;
   int observer_add_read_;
   int observer_did_apply_;
 
-  scoped_ptr<ReadingListModelMemory> model_;
+  std::unique_ptr<ReadingListModelMemory> model_;
 };
 
 TEST_F(ReadingListModelTest, EmptyLoaded) {
   EXPECT_TRUE(model_->loaded());
   AssertObserverCount(1, 0, 0, 0, 0, 0, 0, 0, 0);
   EXPECT_EQ(0ul, model_->unread_size());
   EXPECT_EQ(0ul, model_->read_size());
   model_->Shutdown();
   EXPECT_FALSE(model_->loaded());
   AssertObserverCount(1, 0, 0, 1, 0, 0, 0, 0, 0);
@@ skipping 67 matching lines @@
   auto third_token = model_->BeginBatchUpdates();
   AssertObserverCount(1, 2, 1, 0, 0, 0, 0, 0, 0);
   EXPECT_TRUE(model_->IsPerformingBatchUpdates());
 
   delete third_token.release();
   AssertObserverCount(1, 2, 2, 0, 0, 0, 0, 0, 0);
   EXPECT_FALSE(model_->IsPerformingBatchUpdates());
 }
 
 }  // namespace