[Offline Pages] Turn Offliner::Cancel into an async operation to resolve conflicting assumptions be…

chrome/browser/android/offline_pages/background_loader_offliner.h

Index: chrome/browser/android/offline_pages/background_loader_offliner.h
diff --git a/chrome/browser/android/offline_pages/background_loader_offliner.h b/chrome/browser/android/offline_pages/background_loader_offliner.h
index b08473a17e35438cc4ff885e84b1599c8a51a2bf..4dcd598ba9599177f27d29f1c6240abe3ca5d467 100644
--- a/chrome/browser/android/offline_pages/background_loader_offliner.h
+++ b/chrome/browser/android/offline_pages/background_loader_offliner.h
@@ -38,7 +38,7 @@ class BackgroundLoaderOffliner : public Offliner,
   bool LoadAndSave(const SavePageRequest& request,
                    const CompletionCallback& completion_callback,
                    const ProgressCallback& progress_callback) override;
-  void Cancel() override;
+  void Cancel(const CancelCallback& callback) override;
   bool HandleTimeout(const SavePageRequest& request) override;
 
   // WebContentsObserver implementation.
@@ -69,6 +69,8 @@ class BackgroundLoaderOffliner : public Offliner,
   // Called when application state has changed.
   void OnApplicationStateChange(
       base::android::ApplicationState application_state);
+  void HandleApplicationStateChangeCancel(const SavePageRequest& request,
+                                          int64_t offline_id);
 
   std::unique_ptr<background_loader::BackgroundLoaderContents> loader_;
   // Not owned.
@@ -83,6 +85,7 @@ class BackgroundLoaderOffliner : public Offliner,
   std::unique_ptr<base::android::ApplicationStatusListener> app_listener_;
   // Whether we are on a low-end device.
   bool is_low_end_device_;
+
   // Save state.
   SaveState save_state_;
   // Page load state.
@@ -90,6 +93,9 @@ class BackgroundLoaderOffliner : public Offliner,
   // Seconds to delay before taking snapshot.
   long page_delay_ms_;
 
+  // Callback for cancel.
+  CancelCallback cancel_callback_;
+
   base::WeakPtrFactory<BackgroundLoaderOffliner> weak_ptr_factory_;
   DISALLOW_COPY_AND_ASSIGN(BackgroundLoaderOffliner);
 };