Last_n: disable on Svelte devices.

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 315 matching lines @@
   recent_tab_helper()->WasHidden();
   recent_tab_helper()->ObserveAndDownloadCurrentPage(NewDownloadClientId(),
                                                      123L);
   RunUntilIdle();
   EXPECT_TRUE(model()->is_loaded());
   // No page should be captured.
   EXPECT_EQ(0U, page_added_count());
   ASSERT_EQ(0U, GetAllPages().size());
 }
 
+// Checks that last_n is disabled if the device is low-end (aka svelte) but that
+// download requests still work.
+TEST_F(RecentTabHelperTest, LastNDisabledOnSvelte) {
+  // Simulates a low end device.
+  recent_tab_helper()->is_low_end_device_ = true;
+
+  // Navigate and finish loading then hide the tab. Nothing should be saved.
+  NavigateAndCommit(kTestPageUrl);
+  recent_tab_helper()->DocumentOnLoadCompletedInMainFrame();
+  FastForwardSnapshotController();
+  recent_tab_helper()->WasHidden();
+  RunUntilIdle();
+  EXPECT_TRUE(model()->is_loaded());
+  EXPECT_EQ(0U, page_added_count());
+  ASSERT_EQ(0U, GetAllPages().size());
+
+  // But the following download request should work normally
+  recent_tab_helper()->ObserveAndDownloadCurrentPage(NewDownloadClientId(),
+                                                     123L);
+  RunUntilIdle();
+  EXPECT_EQ(1U, page_added_count());
+  ASSERT_EQ(1U, GetAllPages().size());
+}
+
 // Triggers two last_n snapshot captures during a single page load. Should end
 // up with one snapshot, the 1st being replaced by the 2nd.
 TEST_F(RecentTabHelperTest, TwoCapturesSamePageLoad) {
   NavigateAndCommit(kTestPageUrl);
   // Set page loading state to the 1st snapshot-able stage. No capture so far.
   recent_tab_helper()->DocumentAvailableInMainFrame();
   FastForwardSnapshotController();
   RunUntilIdle();
   EXPECT_TRUE(model()->is_loaded());
   EXPECT_EQ(0U, page_added_count());
@@ skipping 438 matching lines @@
   EXPECT_EQ(2U, page_added_count());
   EXPECT_EQ(0U, model_removed_count());
   ASSERT_EQ(2U, GetAllPages().size());
   const OfflinePageItem* second_page = FindPageForOfflineId(offline_id_3);
   ASSERT_TRUE(second_page);
   EXPECT_EQ(client_id_3, second_page->client_id);
   EXPECT_EQ(offline_id_3, second_page->offline_id);
 }
 
 }  // namespace offline_pages