sync: Attempt to recover from directory corruption

chrome/browser/sync/profile_sync_service.cc

 // 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.
 
 #include "chrome/browser/sync/profile_sync_service.h"
 
 #include <cstddef>
 #include <map>
 #include <set>
 #include <utility>
@@ skipping 682 matching lines @@
     }
     start_up_time_ = base::Time();
   }
 
   if (!success) {
     // Something went unexpectedly wrong.  Play it safe: stop syncing at once
     // and surface error UI to alert the user sync has stopped.
     // Keep the directory around for now so that on restart we will retry
     // again and potentially succeed in presence of transient file IO failures
     // or permissions issues, etc.
+    //
+    // TODO(rlarocque): Consider making this UnrecoverableError less special.
+    // Unlike every other UnrecoverableError, it does not delete our sync data.
+    // This exception made sense at the time it was implemented, but our new
+    // directory corruption recovery mechanism makes it obsolete.  By the time
+    // we get here, we will have already tried and failed to delete the
+    // directory.  It would be no big deal if we tried to delete it again.
     OnInternalUnrecoverableError(FROM_HERE,
                                  "BackendInitialize failure",
                                  false,
                                  ERROR_REASON_BACKEND_INIT_FAILURE);
     return;
   }
 
   backend_initialized_ = true;
 
   sync_js_controller_.AttachJsBackend(js_backend);
@@ skipping 1079 matching lines @@
   // See http://stackoverflow.com/questions/6224121/is-new-this-myclass-undefined-behaviour-after-directly-calling-the-destru.
   ProfileSyncService* old_this = this;
   this->~ProfileSyncService();
   new(old_this) ProfileSyncService(
       new ProfileSyncComponentsFactoryImpl(profile,
                                            CommandLine::ForCurrentProcess()),
       profile,
       signin,
       behavior);
 }