[Offline pages] Fixing crashes caused by access to offline pages marked for deletion

components/offline_pages/offline_page_model_unittest.cc

 // Copyright 2015 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 "components/offline_pages/offline_page_model.h"
 
 #include <algorithm>
 
 #include "base/bind.h"
 #include "base/files/file_util.h"
@@ skipping 582 matching lines @@
 TEST_F(OfflinePageModelTest, MarkPageForDeletion) {
   scoped_ptr<OfflinePageTestArchiver> archiver(
       BuildArchiver(kTestUrl,
                     OfflinePageArchiver::ArchiverResult::SUCCESSFULLY_CREATED)
           .Pass());
   model()->SavePage(
       kTestUrl, kTestPageBookmarkId1, archiver.Pass(),
       base::Bind(&OfflinePageModelTest::OnSavePageDone, AsWeakPtr()));
   PumpLoop();
 
+  GURL offline_url = model()->GetAllPages().begin()->GetOfflineURL();
+
   // Delete the page with undo tiggerred.
   model()->MarkPageForDeletion(
       kTestPageBookmarkId1,
       base::Bind(&OfflinePageModelTest::OnDeletePageDone, AsWeakPtr()));
   PumpLoop();
 
   // GetAllPages will not return the page that is marked for deletion.
   const std::vector<OfflinePageItem>& offline_pages = model()->GetAllPages();
   EXPECT_EQ(0UL, offline_pages.size());
 
+  EXPECT_FALSE(model()->HasOfflinePages());
+  EXPECT_EQ(nullptr, model()->GetPageByOnlineURL(kTestUrl));
+  EXPECT_EQ(nullptr, model()->GetPageByBookmarkId(kTestPageBookmarkId1));
+  EXPECT_EQ(nullptr, model()->GetPageByOfflineURL(offline_url));
+
   // Undo the deletion.
   model()->UndoPageDeletion(kTestPageBookmarkId1);
   base::RunLoop().RunUntilIdle();
 
   // GetAllPages will now return the restored page.
   const std::vector<OfflinePageItem>& offline_pages_after_undo =
       model()->GetAllPages();
   EXPECT_EQ(1UL, offline_pages_after_undo.size());
 }
 
@@ skipping 385 matching lines @@
 
   // Chrome should not crash when a bookmark with no offline copy is changed.
   // http://crbug.com/560518
   bookmark_node.set_url(kTestUrl);
   model()->BookmarkNodeChanged(nullptr, &bookmark_node);
   PumpLoop();
   EXPECT_EQ(0UL, model()->GetAllPages().size());
 }
 
 }  // namespace offline_pages