Last_n: Do not save a snapshot of a closing tab.

chrome/browser/android/offline_pages/recent_tab_helper_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 "chrome/browser/android/offline_pages/recent_tab_helper.h"
 
 #include "base/memory/ptr_util.h"
 #include "base/run_loop.h"
 #include "base/strings/string16.h"
 #include "base/strings/string_number_conversions.h"
@@ skipping 837 matching lines @@
   RunUntilIdle();
   EXPECT_EQ(3U, page_added_count());
   EXPECT_EQ(1U, model_removed_count());
   ASSERT_EQ(2U, GetAllPages().size());
   const OfflinePageItem* downloads_page = FindPageForOfflineId(offline_id);
   EXPECT_EQ(kTestPageUrlWithSegment, downloads_page->url);
   EXPECT_EQ(client_id, downloads_page->client_id);
   EXPECT_EQ(offline_id, downloads_page->offline_id);
 }
 
+// Checks that a closing tab doesn't trigger the creation of a snapshot. And
+// also that if the closure is reverted, a snapshot is saved upon the next hide
+// event.
+TEST_F(RecentTabHelperTest, NoSaveIfTabIsClosing) {
+  // Navigates and fully load then close and hide the tab. No snapshots are
+  // expected.
+  NavigateAndCommit(kTestPageUrl);
+  recent_tab_helper()->DocumentOnLoadCompletedInMainFrame();
+  FastForwardSnapshotController();
+  // Note: These two next calls are always expected to happen in this order.
+  recent_tab_helper()->WillCloseTab();
+  recent_tab_helper()->WasHidden();
+  RunUntilIdle();
+  EXPECT_EQ(0U, page_added_count());
+  EXPECT_EQ(0U, model_removed_count());
+  ASSERT_EQ(0U, GetAllPages().size());
+
+  // Simulates the page being restored and shown again, then hidden. At this
+  // moment a snapshot should be created.
+  recent_tab_helper()->WasShown();
+  recent_tab_helper()->WasHidden();
+  RunUntilIdle();
+  EXPECT_EQ(1U, page_added_count());
+  EXPECT_EQ(0U, model_removed_count());
+  ASSERT_EQ(1U, GetAllPages().size());
+}
+
 }  // namespace offline_pages