[Offline Pages] Moves Coordinator to using MarkAttemptStarted/MarkAttemptCompleted API.

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 <string>
+
 #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:
@@ skipping 39 matching lines @@
   // Clears the currently processing request, if any, and skips running its
   // CompletionCallback.
   virtual void Cancel() = 0;
 
   // TODO(dougarnett): add policy support methods.
 };
 
 }  // namespace offline_pages
 
 #endif  // COMPONENTS_OFFLINE_PAGES_BACKGROUND_OFFLINER_H_