PrerenderingLoader initial integration with PrerenderManager/PrerenderHandle

components/offline_pages/background/offliner.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 COMPONENTS_OFFLINE_PAGES_BACKGROUND_OFFLINER_H_
 #define COMPONENTS_OFFLINE_PAGES_BACKGROUND_OFFLINER_H_
 
 #include "base/callback.h"
 
 namespace offline_pages {
 
 class SavePageRequest;
 
 // Interface of a class responsible for constructing an offline page given
 // a request with a URL.
 class Offliner {
  public:
   // Completion status of processing an offline page request.
   enum CompletionStatus {

[pasko, 2016/05/12 19:10:07]

since there are values like "LOADED" with indication that the request is not
completed yet, having "Completion" in the name is misleading.

Suggesting:

offline_pages::OfflineRequestStatus
offline_pages::Offliner::RequestProgressStatus

[dougarnett, 2016/05/13 00:00:24]

Done.

-    SAVED = 0,
-    CANCELED = 1,
-    FAILED_CONSIDER_RETRY = 2,
-    FAILED_DO_NOT_RETRY = 3,
+    UNKNOWN = 0,                // No completion status determined/reported yet.

[pasko, 2016/05/12 19:10:07]

this value is not used in the code, use it in a test or remove.

[dougarnett, 2016/05/13 00:00:24]

Actually meant to use in unit tests so added initialization.
Or is there decent way to test for undefined value?

+    LOADED = 1,                 // Page loaded but not (yet) saved.
+    SAVED = 2,                  // Offline page snapshot saved.
+    CANCELED = 3,               // Request was canceled.
+    FAILED_CONSIDER_RETRY = 4,  // Failed in a way that is subject to retry.
+    FAILED_DO_NOT_RETRY = 5,

[pasko, 2016/05/12 19:10:07]

do we need numerical constants here?

Scoped enums (i.e. "enum class") are preferable in this case.

[dougarnett, 2016/05/13 00:00:24]

Done.

   };
 
   // Reports the completion status of a request.
   // TODO(dougarnett): consider passing back a request id instead of request.
   typedef base::Callback<void(const SavePageRequest&, CompletionStatus)>
       CompletionCallback;
 
   Offliner() {}
   virtual ~Offliner() {}
 
   // Processes |request| to load and save an offline page.
   // Returns whether the request was accepted or not.
   virtual bool LoadAndSave(
       const SavePageRequest& request,
       const CompletionCallback& callback) = 0;
 
   // Clears the currently processing request, if any.
   virtual void Cancel() = 0;
 
   // TODO(dougarnett): add policy support methods.
 };
 
 }  // namespace offline_pages
 
 #endif  // COMPONENTS_OFFLINE_PAGES_BACKGROUND_OFFLINER_H_