Offline pages using NQE 2G Slow

chrome/browser/android/offline_pages/offline_page_tab_helper.h

 // 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.
 
 #ifndef CHROME_BROWSER_ANDROID_OFFLINE_PAGES_OFFLINE_PAGE_TAB_HELPER_H_
 #define CHROME_BROWSER_ANDROID_OFFLINE_PAGES_OFFLINE_PAGE_TAB_HELPER_H_
 
 #include "base/macros.h"
 #include "base/memory/weak_ptr.h"
 #include "components/offline_pages/offline_page_types.h"
 #include "content/public/browser/web_contents_observer.h"
 #include "content/public/browser/web_contents_user_data.h"
 #include "url/gurl.h"
 
+namespace base {
+class Clock;
+}
+
 namespace content {
 class WebContents;
 }
 
 namespace offline_pages {
 
 struct OfflinePageItem;
 
 // Per-tab class to manage switch between online version and offline version.
 class OfflinePageTabHelper :
@@ skipping 14 matching lines @@
   // The fringe errors (like no OfflinePageModel, etc.) are not reported due
   // to their low probability.
   // NOTE: because this is used for UMA reporting, these values should not be
   // changed or reused; new values should be ended immediately before the MAX
   // value. Make sure to update the histogram enum
   // (OfflinePagesRedirectResult in histograms.xml) accordingly.
   // Public for testing.
   enum class RedirectResult {
     REDIRECTED_ON_DISCONNECTED_NETWORK = 0,
     PAGE_NOT_FOUND_ON_DISCONNECTED_NETWORK = 1,
+    // Flaky Network means the network reported an error when trying to fetch
+    // the resource.
     REDIRECTED_ON_FLAKY_NETWORK = 2,
     PAGE_NOT_FOUND_ON_FLAKY_NETWORK = 3,
     IGNORED_FLAKY_NETWORK_FORWARD_BACK = 4,
     REDIRECTED_ON_CONNECTED_NETWORK = 5,
     NO_TAB_ID = 6,
     SHOW_NET_ERROR_PAGE = 7,
     REDIRECT_LOOP_OFFLINE = 8,
     REDIRECT_LOOP_ONLINE = 9,
+    // Prohibitively slow means that the NetworkQualityEstimator reported a
+    // connection of 2G slow.

[tbansal1, 2016/07/26 20:12:48]

Do not put "2G slow" in the comment as NQE could have returned E_C_T_OFFLINE.
May be simply saying that these enums are used when offline page was used
because NQE reported the network as slow.

[RyanSturm, 2016/07/26 21:48:12]

Done.

+    REDIRECTED_ON_PROHIBITVELY_SLOW_NETWORK = 10,

[tbansal1, 2016/07/26 20:12:48]

s/TV/TIV/

[RyanSturm, 2016/07/26 21:48:12]

Done.

+    PAGE_NOT_FOUND_ON_PROHIBITVELY_SLOW_NETWORK = 11,
+    PAGE_NOT_FRESH_ON_PROHIBITVELY_SLOW_NETWORK = 12,
     REDIRECT_RESULT_MAX,
   };
 
   ~OfflinePageTabHelper() override;
 
   const OfflinePageItem* offline_page() { return offline_page_.get(); }
 
+  // Allow tests to change the freshness of offline pages by using a custom
+  // clock.
+  void SetClockForTesting(std::unique_ptr<base::Clock> clock);

[Dmitry Titov, 2016/07/26 21:10:36]

Drive-by: Note how we use DefaultDelegate to inject dependencies into this
class. Tests will then create their own Delegate and call SetDelegateForTest().
This way, all test code is in Delegate.

[RyanSturm, 2016/07/26 21:48:13]

Done.

+
  private:
   friend class content::WebContentsUserData<OfflinePageTabHelper>;
   friend class OfflinePageTabHelperTest;
   FRIEND_TEST_ALL_PREFIXES(OfflinePageTabHelperTest,
                            NewNavigationCancelsPendingRedirects);
 
   explicit OfflinePageTabHelper(content::WebContents* web_contents);
 
   void SetDelegateForTesting(std::unique_ptr<Delegate> delegate);
 
@@ skipping 26 matching lines @@
   // Returns true if a given URL is in redirect chain already.
   bool IsInRedirectLoop(const GURL& to_url) const;
 
   void ReportRedirectResultUMA(RedirectResult result);
 
   // Iff the tab we are associated with is redirected to an offline page,
   // |offline_page_| will be non-null.  This can be used to synchronously ask
   // about the offline state of the current web contents.
   std::unique_ptr<OfflinePageItem> offline_page_;
   std::unique_ptr<Delegate> delegate_;
+
+  // Typically the default Clock implementation, but can be overriden in tests.
+  std::unique_ptr<base::Clock> clock_;
+
   base::WeakPtrFactory<OfflinePageTabHelper> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(OfflinePageTabHelper);
 };
 
 }  // namespace offline_pages
 
 #endif  // CHROME_BROWSER_ANDROID_OFFLINE_PAGES_OFFLINE_PAGE_TAB_HELPER_H_