Add pause/resume functionality to precache

components/precache/content/precache_manager.h

 // Copyright 2013 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_PRECACHE_CONTENT_PRECACHE_MANAGER_H_
 #define COMPONENTS_PRECACHE_CONTENT_PRECACHE_MANAGER_H_
 
 #include <stddef.h>
 #include <stdint.h>
 
 #include <list>
 #include <memory>
 #include <string>
 #include <utility>
 #include <vector>
 
 #include "base/callback.h"
 #include "base/compiler_specific.h"
 #include "base/macros.h"
 #include "base/memory/weak_ptr.h"
 #include "components/history/core/browser/history_types.h"
 #include "components/keyed_service/core/keyed_service.h"
 #include "components/precache/core/precache_fetcher.h"
 #include "url/gurl.h"
 
 namespace base {
+class FilePath;
 class Time;
 }
 
 namespace content {
 class BrowserContext;
 }
 
 namespace history {
 class HistoryService;
 }
 
 namespace sync_driver {
 class SyncService;
 }
 
 namespace precache {
 
 class PrecacheDatabase;
+class PrecacheUnfinishedWork;
 
 // Visible for test.
 size_t NumTopHosts();
 
 // Class that manages all precaching-related activities. Owned by the
 // BrowserContext that it is constructed for. Use
 // PrecacheManagerFactory::GetForBrowserContext to get an instance of this
 // class. All methods must be called on the UI thread unless indicated
 // otherwise.
 // TODO(sclittle): Delete precache history when browsing history is deleted.
 // http://crbug.com/326549
 class PrecacheManager : public KeyedService,
                         public PrecacheFetcher::PrecacheDelegate,
                         public base::SupportsWeakPtr<PrecacheManager> {
  public:
   typedef base::Callback<void(bool)> PrecacheCompletionCallback;
 
   PrecacheManager(content::BrowserContext* browser_context,
                   const sync_driver::SyncService* const sync_service,
-                  const history::HistoryService* const history_service);
+                  const history::HistoryService* const history_service,
+                  const base::FilePath& db_path,
+                  std::unique_ptr<PrecacheDatabase> precache_database);
   ~PrecacheManager() override;
 
   // Returns true if the client is in the experiment group -- that is,
   // precaching is allowed based on user settings, and enabled as part of a
   // field trial or by commandline flag. Virtual for testing.
   virtual bool IsInExperimentGroup() const;
 
   // Returns true if the client is in the control group -- that is, precaching
   // is allowed based on user settings, and the browser is in the control group
   // of the field trial. Virtual for testing.
@@ skipping 35 matching lines @@
     DISALLOWED,
     PENDING
   };
 
   // From KeyedService.
   void Shutdown() override;
 
   // From PrecacheFetcher::PrecacheDelegate.
   void OnDone() override;
 
+  // Callback when fetching unfinished work from storage is done.
+  void OnGetUnfinishedWorkDone(
+      std::unique_ptr<PrecacheUnfinishedWork> unfinished_work);
+
   // From history::HistoryService::TopHosts.
   void OnHostsReceived(const history::TopHostsList& host_counts);
 
+  // Initializes and Starts a PrecacheFetcher with unfinished work.
+  void InitializeAndStartFetcher();
+
   // From history::HistoryService::TopHosts. Used for the control group, which
   // gets the list of TopHosts for metrics purposes, but otherwise does nothing.
   void OnHostsReceivedThenDone(const history::TopHostsList& host_counts);
 
   // Returns true if precaching is allowed for the browser context.
   AllowedType PrecachingAllowed() const;
 
   // Update precache-related metrics in response to a URL being fetched. Called
   // by RecordStatsForFetch() by way of an asynchronous HistoryService callback.
   void RecordStatsForFetchInternal(const GURL& url,
@@ skipping 22 matching lines @@
   // canceled.
   PrecacheCompletionCallback precache_completion_callback_;
 
   // The PrecacheDatabase for tracking precache metrics. Should only be used on
   // the DB thread.
   std::unique_ptr<PrecacheDatabase> precache_database_;
 
   // Flag indicating whether or not precaching is currently in progress.
   bool is_precaching_;
 
+  // Work that hasn't yet finished.
+  std::unique_ptr<PrecacheUnfinishedWork> unfinished_work_;
+
   DISALLOW_COPY_AND_ASSIGN(PrecacheManager);
 };
 
 }  // namespace precache
 
 #endif  // COMPONENTS_PRECACHE_CONTENT_PRECACHE_MANAGER_H_