[Offline pages] Create offliner that uses background loader

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
new file mode 100644
index 0000000000000000000000000000000000000000..42cbd07e6ff88d475a94ec249fee7e90d4dc4ffb
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+++ b/chrome/browser/android/offline_pages/background_loader_offliner.h
@@ -0,0 +1,77 @@
+// 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_BACKGROUND_LOADER_OFFLINER_H_
+#define CHROME_BROWSER_ANDROID_OFFLINE_PAGES_BACKGROUND_LOADER_OFFLINER_H_
+
+#include <memory>
+
+#include "base/android/application_status_listener.h"
+#include "base/memory/weak_ptr.h"
+#include "components/offline_pages/background/offliner.h"
+#include "components/offline_pages/content/background_loader/background_loader_contents.h"
+#include "components/offline_pages/offline_page_model.h"
+#include "components/offline_pages/offline_page_types.h"
+#include "content/public/browser/web_contents_observer.h"
+
+namespace content {
+class BrowserContext;
+}  // namespace content
+
+namespace offline_pages {
+
+class OfflinerPolicy;
+
+// An Offliner implementation that attempts client-side rendering and saving
+// of an offline page. It uses the BackgroundLoader to load the page and the
+// OfflinePageModel to save it. Only one request may be active at a time.
+class BackgroundLoaderOffliner : public Offliner,
+                                 public content::WebContentsObserver {
+ public:
+  explicit BackgroundLoaderOffliner(content::BrowserContext* browser_context,
+                                    const OfflinerPolicy* policy,
+                                    OfflinePageModel* offline_page_model);
+  ~BackgroundLoaderOffliner() override;
+
+  // Offliner implementation
+  bool LoadAndSave(const SavePageRequest& request,
+                   const CompletionCallback& callback) override;
+  void Cancel() override;
+
+  // WebContentsObserver implementation
+  void DidStopLoading() override;
+
+ private:
+  friend class TestBackgroundContentsOffliner;
+  // Called when the page has been saved.
+  void OnPageSaved(SavePageResult save_result, int64_t offline_id);
+
+  // Called to reset internal loader and observer state.
+  // TODO(chili): Remove after RequestCoordinator can handle multiple offliners.
+  void ResetState();
+
+  // Called when application state has changed.
+  void OnApplicationStateChange(
+      base::android::ApplicationState application_state);
+
+  // Not owned.
+  content::BrowserContext* browser_context_;
+  // Not owned.
+  OfflinePageModel* offline_page_model_;
+  // Tracks pending request, if any.
+  std::unique_ptr<SavePageRequest> pending_request_;
+  // Callback when pending request completes.
+  CompletionCallback completion_callback_;
+  std::unique_ptr<background_loader::BackgroundLoaderContents> loader_;
+  // ApplicationStatusListener to monitor if Chrome moves to the foreground.
+  std::unique_ptr<base::android::ApplicationStatusListener> app_listener_;
+  // Whether we are on a low-end device.

[Pete Williamson, 2016/12/01 02:03:38]

We needed to track this for the prerenderer, because we know it had problems on
svelte devices.  Do you think your offliner will have problems on svelte
devices, or are you just allowing for the possibility?

[chili, 2016/12/09 22:45:57]

I'm allowing for possibility.  We can remove later after more testing

+  bool is_low_end_device_;
+
+  base::WeakPtrFactory<BackgroundLoaderOffliner> weak_ptr_factory_;
+  DISALLOW_COPY_AND_ASSIGN(BackgroundLoaderOffliner);
+};
+
+}  // namespace offline_pages
+#endif  // CHROME_BROWSER_ANDROID_OFFLINE_PAGES_BACKGROUND_LOADER_OFFLINER_H_