chromeos: Destruct DriveResourceMetadata on the blocking pool

chrome/browser/chromeos/drive/drive_resource_metadata.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/chromeos/drive/drive_resource_metadata.h"
 
 #include <leveldb/db.h>
 #include <stack>
 #include <utility>
 
@@ skipping 144 matching lines @@
 DriveResourceMetadata::DriveResourceMetadata(
     const std::string& root_resource_id,
     scoped_refptr<base::SequencedTaskRunner> blocking_task_runner)
     : blocking_task_runner_(blocking_task_runner),
       storage_(new DriveResourceMetadataStorageMemory),
       root_resource_id_(root_resource_id),
       serialized_size_(0),
       largest_changestamp_(0),
       loaded_(false),
       ALLOW_THIS_IN_INITIALIZER_LIST(weak_ptr_factory_(this)) {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
+
   DriveEntryProto root;
   root.mutable_file_info()->set_is_directory(true);
   root.set_resource_id(root_resource_id);
   root.set_title(kDriveRootDirectory);
   storage_->PutEntry(CreateEntryWithProperBaseName(root));
 }
 
+void DriveResourceMetadata::Destroy() {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
+
+  ClearRoot();
+  weak_ptr_factory_.InvalidateWeakPtrs();
+  blocking_task_runner_->PostTask(
+      FROM_HERE,
+      base::Bind(&DriveResourceMetadata::DestroyOnBlockingPool,
+                 base::Unretained(this)));
+}
+
 DriveResourceMetadata::~DriveResourceMetadata() {
-  ClearRoot();
+  DCHECK(blocking_task_runner_->RunsTasksOnCurrentThread());
+}
+
+void DriveResourceMetadata::DestroyOnBlockingPool() {
+  DCHECK(blocking_task_runner_->RunsTasksOnCurrentThread());
+  delete this;
 }
 
 void DriveResourceMetadata::ClearRoot() {
   if (root_resource_id_.empty())
     return;
 
   RemoveDirectoryChildren(root_resource_id_);
   storage_->RemoveEntry(root_resource_id_);
   root_resource_id_.clear();
 }
@@ skipping 683 matching lines @@
       CreateEntryWithProperBaseName(proto.drive_directory().drive_entry()));
   AddDescendantsFromProto(proto.drive_directory());
 
   loaded_ = true;
   largest_changestamp_ = proto.largest_changestamp();
 
   return true;
 }
 
 }  // namespace drive