Make reading list entry movable only

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_impl.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 namespace {
 
 class ReadingListModelTest : public ReadingListModelObserver,
@@ skipping 110 matching lines @@
   AssertObserverCount(1, 0, 0, 0, 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, 0, 0, 0);
 }
 
 TEST_F(ReadingListModelTest, AddEntry) {
   ClearCounts();
-  const ReadingListEntry entry =
+  const ReadingListEntry& entry =
       model_->AddEntry(GURL("http://example.com"), "sample");
   EXPECT_EQ(GURL("http://example.com"), entry.URL());
   EXPECT_EQ("sample", entry.Title());
 
   AssertObserverCount(0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1);
   EXPECT_EQ(1ul, model_->unread_size());
   EXPECT_EQ(0ul, model_->read_size());
   EXPECT_TRUE(model_->HasUnseenEntries());
 
-  const ReadingListEntry other_entry = model_->GetUnreadEntryAtIndex(0);
+  const ReadingListEntry& other_entry = model_->GetUnreadEntryAtIndex(0);
   EXPECT_EQ(GURL("http://example.com"), other_entry.URL());
   EXPECT_EQ("sample", other_entry.Title());
 }
 
 TEST_F(ReadingListModelTest, ReadEntry) {
-  const ReadingListEntry entry =
-      model_->AddEntry(GURL("http://example.com"), "sample");
+  model_->AddEntry(GURL("http://example.com"), "sample");
 
   ClearCounts();
   model_->MarkReadByURL(GURL("http://example.com"));
   AssertObserverCount(0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1);
   EXPECT_EQ(0ul, model_->unread_size());
   EXPECT_EQ(1ul, model_->read_size());
   EXPECT_FALSE(model_->HasUnseenEntries());
 
-  const ReadingListEntry other_entry = model_->GetReadEntryAtIndex(0);
+  const ReadingListEntry& other_entry = model_->GetReadEntryAtIndex(0);
   EXPECT_EQ(GURL("http://example.com"), other_entry.URL());
   EXPECT_EQ("sample", other_entry.Title());
 }
 
 TEST_F(ReadingListModelTest, BatchUpdates) {
   auto token = model_->BeginBatchUpdates();
   AssertObserverCount(1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0);
   EXPECT_TRUE(model_->IsPerformingBatchUpdates());
 
   delete token.release();
@@ skipping 94 matching lines @@
   const ReadingListEntry& entry = model_->GetReadEntryAtIndex(0);
   ClearCounts();
 
   model_->SetEntryDistilledURL(gurl, gurl);
   AssertObserverCount(0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1);
   EXPECT_EQ(ReadingListEntry::PROCESSED, entry.DistilledState());
   EXPECT_EQ(gurl, entry.DistilledURL());
 }
 
 }  // namespace