Convert LocalToRemoteSyncer::Continuation to OnceCallback

This CL changes LocalToRemoteSyncer::Continuation from Callback to
OnceCallback.

Bug: 1152272
Change-Id: Ie839b5982775429332c48d9c3930151a74f42423
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2604677
Commit-Queue: Thomas Guilbert <tguilbert@chromium.org>
Commit-Queue: Victor Costan <pwnall@chromium.org>
Auto-Submit: Thomas Guilbert <tguilbert@chromium.org>
Reviewed-by: Victor Costan <pwnall@chromium.org>
Cr-Commit-Position: refs/heads/master@{#840307}

chrome/browser/sync_file_system/drive_backend/local_to_remote_syncer.cc

@@ -253,7 +253,7 @@ void LocalToRemoteSyncer::RunPreflight(std::unique_ptr<SyncTaskToken> token) {
 }
 
 void LocalToRemoteSyncer::MoveToBackground(
-    const Continuation& continuation,
+    Continuation continuation,
     std::unique_ptr<SyncTaskToken> token) {
   std::unique_ptr<TaskBlocker> blocker(new TaskBlocker);
   blocker->app_id = url_.origin().host();
@@ -277,11 +277,11 @@ void LocalToRemoteSyncer::MoveToBackground(
   SyncTaskManager::UpdateTaskBlocker(
       std::move(token), std::move(blocker),
       base::BindOnce(&LocalToRemoteSyncer::ContinueAsBackgroundTask,
-                     weak_ptr_factory_.GetWeakPtr(), continuation));
+                     weak_ptr_factory_.GetWeakPtr(), std::move(continuation)));
 }
 
 void LocalToRemoteSyncer::ContinueAsBackgroundTask(
-    const Continuation& continuation,
+    Continuation continuation,
     std::unique_ptr<SyncTaskToken> token) {
   // The SyncTask runs as a background task beyond this point.
   // Note that any task can run between MoveToBackground() and
@@ -315,7 +315,7 @@ void LocalToRemoteSyncer::ContinueAsBackgroundTask(
     }
   }
 
-  continuation.Run(std::move(token));
+  std::move(continuation).Run(std::move(token));
 }
 
 void LocalToRemoteSyncer::SyncCompleted(std::unique_ptr<SyncTaskToken> token,

chrome/browser/sync_file_system/drive_backend/local_to_remote_syncer.h

@@ -39,7 +39,7 @@ class SyncEngineContext;
 
 class LocalToRemoteSyncer : public SyncTask {
  public:
-  typedef base::Callback<void(std::unique_ptr<SyncTaskToken>)> Continuation;
+  typedef base::OnceCallback<void(std::unique_ptr<SyncTaskToken>)> Continuation;
 
   LocalToRemoteSyncer(SyncEngineContext* sync_context,
                       const SyncFileMetadata& local_metadata,
@@ -58,9 +58,9 @@ class LocalToRemoteSyncer : public SyncTask {
   }
 
  private:
-  void MoveToBackground(const Continuation& continuation,
+  void MoveToBackground(Continuation continuation,
                         std::unique_ptr<SyncTaskToken> token);
-  void ContinueAsBackgroundTask(const Continuation& continuation,
+  void ContinueAsBackgroundTask(Continuation continuation,
                                 std::unique_ptr<SyncTaskToken> token);
   void SyncCompleted(std::unique_ptr<SyncTaskToken> token,
                      SyncStatusCode status);

chrome/browser/sync_file_system/drive_backend/sync_engine_initializer.h

@@ -72,8 +72,6 @@ class SyncEngineInitializer : public SyncTask {
   std::unique_ptr<MetadataDatabase> PassMetadataDatabase();
 
  private:
-  typedef base::Callback<void(SyncStatusCallback callback)> Task;
-
   void GetAboutResource(std::unique_ptr<SyncTaskToken> token);
   void DidGetAboutResource(
       std::unique_ptr<SyncTaskToken> token,