Delete GenericChangeProcessor synchronously when possible.

components/sync_driver/shared_change_processor.cc

 // Copyright 2014 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 "components/sync_driver/shared_change_processor.h"
 
 #include "base/message_loop/message_loop_proxy.h"
 #include "components/sync_driver/generic_change_processor.h"
 #include "components/sync_driver/generic_change_processor_factory.h"
 #include "components/sync_driver/sync_api_component_factory.h"
 #include "sync/api/sync_change.h"
 
 using base::AutoLock;
 
 namespace sync_driver {
 
 SharedChangeProcessor::SharedChangeProcessor()
     : disconnected_(false),
       type_(syncer::UNSPECIFIED),
       frontend_loop_(base::MessageLoopProxy::current()),
       generic_change_processor_(NULL),
       error_handler_(NULL) {
 }
 
 SharedChangeProcessor::~SharedChangeProcessor() {
   // We can either be deleted when the DTC is destroyed (on UI
-  // thread), or when the syncer::SyncableService stop's syncing (datatype
+  // thread), or when the syncer::SyncableService stops syncing (datatype
   // thread).  |generic_change_processor_|, if non-NULL, must be
   // deleted on |backend_loop_|.
-  if (frontend_loop_->BelongsToCurrentThread()) {
-    if (backend_loop_.get()) {
+  if (backend_loop_.get()) {
+    if (backend_loop_->BelongsToCurrentThread()) {
+      delete generic_change_processor_;
+    } else {
+      DCHECK(frontend_loop_->BelongsToCurrentThread());
       if (!backend_loop_->DeleteSoon(FROM_HERE, generic_change_processor_)) {
         NOTREACHED();
       }
-    } else {
-      DCHECK(!generic_change_processor_);
     }
   } else {
-    DCHECK(backend_loop_.get());
-    DCHECK(backend_loop_->BelongsToCurrentThread());
-    delete generic_change_processor_;
+    DCHECK(!generic_change_processor_);
   }
 }
 
 base::WeakPtr<syncer::SyncableService> SharedChangeProcessor::Connect(
     SyncApiComponentFactory* sync_factory,
     GenericChangeProcessorFactory* processor_factory,
     syncer::UserShare* user_share,
     DataTypeErrorHandler* error_handler,
     syncer::ModelType type,
     const base::WeakPtr<syncer::SyncMergeResult>& merge_result) {
@@ skipping 150 matching lines @@
     return error_handler_->CreateAndUploadError(location, message, type_);
   } else {
     return syncer::SyncError(location,
                              syncer::SyncError::DATATYPE_ERROR,
                              message,
                              type_);
   }
 }
 
 }  // namespace sync_driver