IndexedDBFactory now ForceCloses databases.

content/browser/indexed_db/indexed_db_database.cc

 // Copyright (c) 2013 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 "content/browser/indexed_db/indexed_db_database.h"
 
 #include <math.h>
 #include <set>
 
 #include "base/auto_reset.h"
@@ skipping 1571 matching lines @@
   }
   metadata_.version = kNoStringVersion;
   metadata_.id = kInvalidId;
   metadata_.int_version = IndexedDBDatabaseMetadata::NO_INT_VERSION;
   metadata_.object_stores.clear();
   callbacks->OnSuccess();
   if (factory_)
     factory_->DatabaseDeleted(identifier_);
 }
 
+void IndexedDBDatabase::ForceClose() {
+  // The database is also released when the last connection is closed. Because
+  // of this we make a copy of this db's connections as this object *will* be
+  // deleted before this function returns.

[jsbell, 2014/01/03 00:34:25]

A more common pattern is to take a self-reference within the method:

scoped_refptr<IndexedDBTransaction> protect(this);

That also protects against additional logic being added to the method. 

[cmumford, 2014/01/03 21:34:01]

Yes, a much better approach. I'll do that.

+  ConnectionSet conns(connections_);
+  for (ConnectionSet::iterator it = conns.begin(); it != conns.end(); ++it)
+    (*it)->ForceClose();
+  // This object has now been deleted!
+}
+
 void IndexedDBDatabase::Close(IndexedDBConnection* connection, bool forced) {
   DCHECK(connections_.count(connection));
   DCHECK(connection->IsConnected());
   DCHECK(connection->database() == this);
 
   // Abort outstanding transactions from the closing connection. This
   // can not happen if the close is requested by the connection itself
   // as the front-end defers the close until all transactions are
   // complete, but can occur on process termination or forced close.
   {
@@ skipping 58 matching lines @@
     const base::string16& previous_version,
     int64 previous_int_version,
     IndexedDBTransaction* transaction) {
   IDB_TRACE("IndexedDBDatabase::VersionChangeAbortOperation");
   DCHECK(!transaction);
   metadata_.version = previous_version;
   metadata_.int_version = previous_int_version;
 }
 
 }  // namespace content