IndexedDBFactory now ForceCloses databases.

content/browser/indexed_db/indexed_db_database.cc

Index: content/browser/indexed_db/indexed_db_database.cc
diff --git a/content/browser/indexed_db/indexed_db_database.cc b/content/browser/indexed_db/indexed_db_database.cc
index 881c85985e2e84808300b02a1ce724cb3ad87084..8d39e56dac5372c926e89044d84175363a6690e5 100644
--- a/content/browser/indexed_db/indexed_db_database.cc
+++ b/content/browser/indexed_db/indexed_db_database.cc
@@ -1646,6 +1646,12 @@ void IndexedDBDatabase::DeleteDatabaseFinal(
     factory_->DatabaseDeleted(identifier_);
 }
 
+void IndexedDBDatabase::ForceClose() {
+  ConnectionSet conns(connections_);

[jsbell, 2013/12/20 00:24:42]

Is this copy necessary?

[cmumford, 2013/12/20 18:09:26]

I can't see an alternative. listset has no front method, so I can't do a while
(!empty) type of loop. Nor does it have a reverse_iterator. And ForceClose
modifies connections_ which invalidates the iterator and causes a crash. Let me
know if I'm missing something.

[jsbell, 2013/12/20 18:22:56]

A few possibilities:

* list_set does have begin() - should be equivalent to front()

* unless there's a bug, the iterator shouldn't be invalidated during
modification if it's incremented before the removal, similar to the STL
erase(it++) idiom:

it = set.begin();
while (it != set.end()) {
  con = *it;
  ++it;
  con->ForceClose();
}

* a common pattern in these cases is to do a swap rather than a copy. However,
that would empty out the "master" set, and there may be things that rely on
things being in the set. I'd avoid this if possible.

* Finally, if a copy is necessary, document it with a comment (since it's
unusual)

+  for (ConnectionSet::iterator i = conns.begin(); i != conns.end(); ++i)

[jsbell, 2013/12/20 00:24:42]

Nit: We try not to use single-character variables. Prefer "it" or "iter" here.

[cmumford, 2013/12/20 18:09:26]

Done.

+    (*i)->ForceClose();
+}
+
 void IndexedDBDatabase::Close(IndexedDBConnection* connection, bool forced) {
   DCHECK(connections_.count(connection));
   DCHECK(connection->IsConnected());