[Sync] Handle errors during first sync gracefully.

chrome/browser/sync/glue/sync_backend_host.h

 // Copyright (c) 2012 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_SYNC_GLUE_SYNC_BACKEND_HOST_H_
 #define CHROME_BROWSER_SYNC_GLUE_SYNC_BACKEND_HOST_H_
 #pragma once
 
 #include <string>
 
@@ skipping 46 matching lines @@
   //
   // |js_backend| is what about:sync interacts with; it's different
   // from the 'Backend' in 'OnBackendInitialized' (unfortunately).  It
   // is initialized only if |success| is true.
   virtual void OnBackendInitialized(
       const WeakHandle<JsBackend>& js_backend, bool success) = 0;
 
   // The backend queried the server recently and received some updates.
   virtual void OnSyncCycleCompleted() = 0;
 
+  // Configure ran into some kind of error. But it is scheduled to be
+  // retried.
+  virtual void OnSyncConfigureRetry() = 0;
+
   // The backend encountered an authentication problem and requests new
   // credentials to be provided. See SyncBackendHost::Authenticate for details.
   virtual void OnAuthError() = 0;
 
   // We are no longer permitted to communicate with the server. Sync should
   // be disabled and state cleaned up at once.
   virtual void OnStopSyncingPermanently() = 0;
 
   // Called to handle success/failure of clearing server data
   virtual void OnClearServerDataSucceeded() = 0;
@@ skipping 116 matching lines @@
 
   // Changes the set of data types that are currently being synced.
   // The ready_task will be run when configuration is done with the
   // set of all types that failed configuration (i.e., if its argument
   // is non-empty, then an error was encountered).
   virtual void ConfigureDataTypes(
       syncable::ModelTypeSet types_to_add,
       syncable::ModelTypeSet types_to_remove,
       sync_api::ConfigureReason reason,
       base::Callback<void(syncable::ModelTypeSet)> ready_task,
+      base::Callback<void()> retry_callback,
       bool enable_nigori);
 
   // Makes an asynchronous call to syncer to switch to config mode. When done
   // syncer will call us back on FinishConfigureDataTypes.
   virtual void StartConfiguration(const base::Closure& callback);
 
   // Turns on encryption of all present and future sync data.
   virtual void EnableEncryptEverything();
 
   // Activates change processing for the given data type.  This must
@@ skipping 116 matching lines @@
 
   struct PendingConfigureDataTypesState {
     PendingConfigureDataTypesState();
     ~PendingConfigureDataTypesState();
 
     // The ready_task will be run when configuration is done with the
     // set of all types that failed configuration (i.e., if its
     // argument is non-empty, then an error was encountered).
     base::Callback<void(syncable::ModelTypeSet)> ready_task;
 
+    // The retry callback will be run when the download failed due to a
+    // transient error. This is to notify DTM so it can apropriately inform
+    // the UI. Note: The retry_callback will be run only once and after
+    // that we will not notify DTM until the sync is succesful or in a

[Andrew T Wilson (Slow), 2012/01/27 00:19:03]

nit: succesful->successful

[lipalani1, 2012/01/27 02:54:29]

Done.

+    // permanent error state.
+    base::Callback<void()> retry_callback;
+
     // The set of types that we are waiting to be initially synced in a
     // configuration cycle.
     syncable::ModelTypeSet types_to_add;
 
     // Additional details about which types were added.
     syncable::ModelTypeSet added_types;
     sync_api::ConfigureReason reason;
+    bool retry_in_progress;
   };
 
   // Checks if we have received a notice to turn on experimental datatypes
   // (via the nigori node) and informs the frontend if that is the case.
   // Note: it is illegal to call this before the backend is initialized.
   void AddExperimentalTypes();
 
+  // Downloading of nigori failed and will be retried.
+  virtual void OnNigoriDownloadRetry();
+
   // InitializationComplete passes through the SyncBackendHost to forward
   // on to |frontend_|, and so that tests can intercept here if they need to
   // set up initial conditions.
   virtual void HandleInitializationCompletedOnFrontendLoop(
       const WeakHandle<JsBackend>& js_backend,
       bool success);
 
   // Helpers to persist a token that can be used to bootstrap sync encryption
   // across browser restart to avoid requiring the user to re-enter their
   // passphrase.  |token| must be valid UTF-8 as we use the PrefService for
@@ skipping 109 matching lines @@
 
   // UI-thread cache of the last SyncSessionSnapshot received from syncapi.
   scoped_ptr<sessions::SyncSessionSnapshot> last_snapshot_;
 
   DISALLOW_COPY_AND_ASSIGN(SyncBackendHost);
 };
 
 }  // namespace browser_sync
 
 #endif  // CHROME_BROWSER_SYNC_GLUE_SYNC_BACKEND_HOST_H_