Sync FileSystem: Drop is_fetching_changes_ flag and completion_callback

chrome/browser/sync_file_system/drive_file_sync_service.cc

Index: chrome/browser/sync_file_system/drive_file_sync_service.cc
diff --git a/chrome/browser/sync_file_system/drive_file_sync_service.cc b/chrome/browser/sync_file_system/drive_file_sync_service.cc
index 171853aa703b7b7265d207e34448610e98a6c10a..84b71ea44ba7ed7c8b28cfffef213a3795bb3f9f 100644
--- a/chrome/browser/sync_file_system/drive_file_sync_service.cc
+++ b/chrome/browser/sync_file_system/drive_file_sync_service.cc
@@ -52,7 +52,7 @@ const char kDriveInvalidationObjectId[] = "CHANGELOG";
 // notifications are on or off.
 const int64 kMinimumPollingDelaySeconds = 5;
 const int64 kMaximumPollingDelaySeconds = 10 * 60;  // 10 min
-const int64 kPollingDelaySecondsWithNotification = 4 * 60 * 60;  // 4 hr
+const int64 kPollingDelaySecondsWithNotification = 10 * 60;  // 10 min
 const double kDelayMultiplier = 1.6;
 
 bool CreateTemporaryFile(const FilePath& dir_path, FilePath* temp_file) {
@@ -75,10 +75,6 @@ void DeleteTemporaryFile(const FilePath& file_path) {
 
 void EmptyStatusCallback(fileapi::SyncStatusCode code) {}
 
-void MarkFetchingChangesCompleted(bool* is_fetching_changes) {
-  *is_fetching_changes = false;
-}
-
 void DidRemoveOrigin(const GURL& origin, fileapi::SyncStatusCode status) {
   // TODO(calvinlo): Disable syncing if status not ok (http://crbug.com/171611).
   DCHECK_EQ(fileapi::SYNC_STATUS_OK, status);
@@ -110,9 +106,6 @@ class DriveFileSyncService::TaskToken {
     location_ = location;
     task_type_ = TASK_TYPE_NONE;
     description_.clear();
-    if (!completion_callback_.is_null())
-      completion_callback_.Run();
-    completion_callback_.Reset();
   }
 
   void UpdateTask(const tracked_objects::Location& location,
@@ -131,14 +124,6 @@ class DriveFileSyncService::TaskToken {
   const std::string& description() const { return description_; }
   std::string done_description() const { return description_ + " done"; }
 
-  void set_completion_callback(const base::Closure& callback) {
-    completion_callback_ = callback;
-  }
-
-  const base::Closure& completion_callback() {
-    return completion_callback_;
-  }
-
   ~TaskToken() {
     // All task on DriveFileSyncService must hold TaskToken instance to ensure
     // no other tasks are running. Also, as soon as a task finishes to work,
@@ -157,7 +142,6 @@ class DriveFileSyncService::TaskToken {
   tracked_objects::Location location_;
   TaskType task_type_;
   std::string description_;
-  base::Closure completion_callback_;
 
   DISALLOW_COPY_AND_ASSIGN(TaskToken);
 };
@@ -186,6 +170,7 @@ void DriveFileSyncService::OnIncomingInvalidation(
       kDriveInvalidationObjectId);
   DCHECK_EQ(1U, invalidation_map.count(object_id));
 
+  has_unfetched_remote_change_ = true;
   FetchChangesForIncrementalSync();
 }
 
@@ -287,7 +272,7 @@ DriveFileSyncService::DriveFileSyncService(Profile* profile)
       push_notification_registered_(false),
       push_notification_enabled_(false),
       polling_delay_seconds_(kMinimumPollingDelaySeconds),
-      is_fetching_changes_(false),
+      has_unfetched_remote_change_(true),
       weak_factory_(ALLOW_THIS_IN_INITIALIZER_LIST(this)) {
   temporary_file_dir_ =
       profile->GetPath().Append(kSyncFileSystemDir).Append(kTempDirName);
@@ -707,7 +692,7 @@ DriveFileSyncService::DriveFileSyncService(
       push_notification_registered_(false),
       push_notification_enabled_(false),
       polling_delay_seconds_(-1),
-      is_fetching_changes_(false),
+      has_unfetched_remote_change_(true),
       weak_factory_(ALLOW_THIS_IN_INITIALIZER_LIST(this)) {
   DCHECK(profile);
   temporary_file_dir_ = base_dir.Append(kTempDirName);
@@ -767,9 +752,6 @@ void DriveFileSyncService::NotifyTaskDone(fileapi::SyncStatusCode status,
     }
   }
 
-  if (!token_->completion_callback().is_null())
-    token_->completion_callback().Run();
-
   token_->ResetTask(FROM_HERE);
   if (!pending_tasks_.empty()) {
     base::Closure closure = pending_tasks_.front();
@@ -778,10 +760,14 @@ void DriveFileSyncService::NotifyTaskDone(fileapi::SyncStatusCode status,
     return;
   }
 
+  if (has_unfetched_remote_change_ && push_notification_enabled_) {
+    FetchChangesForIncrementalSync();
+    return;
+  }
+
   SchedulePolling();
 
-  if (GetCurrentState() != REMOTE_SERVICE_OK &&
-      GetCurrentState() != REMOTE_SERVICE_TEMPORARY_UNAVAILABLE)
+  if (GetCurrentState() != REMOTE_SERVICE_OK)
     return;
 
   // If the state has become OK or TEMPORARY_UNAVAILABLE and we have any
@@ -1837,42 +1823,17 @@ bool DriveFileSyncService::GetPendingChangeForFileSystemURL(
 }
 
 void DriveFileSyncService::FetchChangesForIncrementalSync() {
-  scoped_ptr<TaskToken> token(GetToken(FROM_HERE, TASK_TYPE_DRIVE,
-                                       "Fetching remote change list"));
-  // If we got |token| successfully, |is_fetching_changes_| should be false.
-  // |is_fetching_changes_| is true only when the FetchChanges sequence is
-  // running or is in |pending_queue_|. In both case, the token is owned by
-  // the FetchChanges sequence.
-  DCHECK(!token || !is_fetching_changes_);
-
   if (!sync_enabled_ ||
-      is_fetching_changes_ ||
       !pending_batch_sync_origins_.empty() ||
       metadata_store_->incremental_sync_origins().empty() ||
-      !pending_changes_.empty()) {
-    if (token) {
-      token->ResetTask(FROM_HERE);
-      NotifyTaskDone(last_operation_status_, token.Pass());
-    }
+      !pending_changes_.empty())
     return;
-  }
-
-  is_fetching_changes_ = true;
-
-  if (!token) {
-    pending_tasks_.push_back(base::Bind(
-        &DriveFileSyncService::FetchChangesForIncrementalSync, AsWeakPtr()));
-    return;
-  }
 
-  token->set_completion_callback(
-      base::Bind(&MarkFetchingChangesCompleted, &is_fetching_changes_));
-
-  if (metadata_store_->incremental_sync_origins().empty()) {
-    token->ResetTask(FROM_HERE);
-    NotifyTaskDone(fileapi::SYNC_STATUS_OK, token.Pass());
+  scoped_ptr<TaskToken> token(GetToken(FROM_HERE, TASK_TYPE_DRIVE,
+                                       "Fetching remote change list"));
+  if (!token)
     return;
-  }
+  has_unfetched_remote_change_ = false;
 
   DVLOG(1) << "FetchChangesForIncrementalSync (start_changestamp:"
            << (largest_fetched_changestamp_ + 1) << ")";