Implementing recent pages snapshot capture.

chrome/browser/android/offline_pages/recent_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_RECENT_TAB_HELPER_H_
 #define CHROME_BROWSER_ANDROID_OFFLINE_PAGES_RECENT_TAB_HELPER_H_
 
+#include <memory>
+#include <vector>
+
+#include "base/memory/weak_ptr.h"
+#include "components/offline_pages/offline_page_model.h"
+#include "components/offline_pages/snapshot_controller.h"
 #include "content/public/browser/web_contents_observer.h"
 #include "content/public/browser/web_contents_user_data.h"
+#include "url/gurl.h"
+
+namespace content {
+class NavigationEntry;
+class NavigationHandle;
+}
 
 namespace offline_pages {
 
 // Attaches to every WebContent shown in a tab. Waits until the WebContent is
 // loaded to proper degree and then makes a snapshot of the page. Removes the
 // oldest snapshot in the 'ring buffer'. As a result, there is always up to N
 // snapshots of recent pages on the device.
 class RecentTabHelper
     : public content::WebContentsObserver,
-      public content::WebContentsUserData<RecentTabHelper> {
+      public content::WebContentsUserData<RecentTabHelper>,
+      public OfflinePageModel::Observer,
+      public SnapshotController::Client {
  public:
   ~RecentTabHelper() override;
 
+  // content::WebContentsObserver
+  void DidFinishNavigation(
+      content::NavigationHandle* navigation_handle) override;
+  void DocumentAvailableInMainFrame() override;
+  void DocumentOnLoadCompletedInMainFrame() override;
+
+  // OfflinePageModel::Observer
+  void OfflinePageModelLoaded(OfflinePageModel* model) override;
+  void OfflinePageModelChanged(offline_pages::OfflinePageModel*) override {};
+  void OfflinePageDeleted(int64_t, const offline_pages::ClientId&) override {};
+
+  // SnapshotController::Client
+  void StartSnapshot() override;
+
+  // Test support.
+  // A factory that supplies the instances of an OfflienPageArchiver.

[dewittj, 2016/05/02 19:54:27]

nit: spelling offlien

+  // This is used for testing, where we want to use a specific mock.
+  class TestArchiveFactory {
+   public:
+    virtual ~TestArchiveFactory() {}
+    virtual std::unique_ptr<OfflinePageArchiver> CreateArchiver(
+        content::WebContents* web_contents) = 0;
+  };
+  // Test method, overrides the normally used MHTML Archivers with a test
+  // mocks created by specified function.
+  void SetArchiveFactoryForTest(
+      std::unique_ptr<TestArchiveFactory> test_archive_factory);
+  // Test method, overrides the task_runner_ so FastForwardBy() can be used.
+  void SetTaskRunnerForTest(
+      const scoped_refptr<base::SingleThreadTaskRunner>& task_runner);
+
  private:
   explicit RecentTabHelper(content::WebContents* web_contents);
   friend class content::WebContentsUserData<RecentTabHelper>;
 
+  void ContinueSnapshotWithModel();
+  void ContinueSnapshotAfterPurge(OfflinePageModel::DeletePageResult result);
+  void SavePageCallback(OfflinePageModel::SavePageResult result,
+                        int64_t offline_id);
+  OfflinePageModel* GetPageModel();
+  std::vector<int64_t> GetPagesToPurge() const;
+  void ReportSnapshotCompleted();
+  bool IsSamePage() const;
+  ClientId client_id() const;
+
+  // Page model is a service, no ownership.
+  OfflinePageModel* page_model_;
+  bool page_model_is_loaded_;
+
+  // If true, never make snapshots off the attached WebContents.
+  bool never_do_snapshots_;
+
+  // The URL of the page that is currently being snapshotted. Used to check,
+  // during async operations, that WebContents still contains the same page.
+  GURL snapshot_url_;
+  std::unique_ptr<SnapshotController> snapshot_controller_;
+  std::unique_ptr<TestArchiveFactory> test_archive_factory_;
+
+  base::WeakPtrFactory<RecentTabHelper> weak_ptr_factory_;
+
   DISALLOW_COPY_AND_ASSIGN(RecentTabHelper);
 };
 
 }  // namespace offline_pages
 #endif  // CHROME_BROWSER_ANDROID_OFFLINE_PAGES_RECENT_TAB_HELPER_H_