Reland: [IndexedDB] Delete callbacks state on worker thread exit.

content/child/indexed_db/indexed_db_dispatcher.cc

Index: content/child/indexed_db/indexed_db_dispatcher.cc
diff --git a/content/child/indexed_db/indexed_db_dispatcher.cc b/content/child/indexed_db/indexed_db_dispatcher.cc
index aafd24419d65f749c47d08f81e01134920406d48..f4da66328242b34be6526c9f4350d87482e3904e 100644
--- a/content/child/indexed_db/indexed_db_dispatcher.cc
+++ b/content/child/indexed_db/indexed_db_dispatcher.cc
@@ -61,6 +61,10 @@ IndexedDBDispatcher::~IndexedDBDispatcher() {
 
   DCHECK(pending_callbacks_.IsEmpty());
 
+  in_destructor_ = true;
+  mojo_owned_callback_state_.clear();
+  mojo_owned_database_callback_state_.clear();
+
   g_idb_dispatcher_tls.Pointer()->Set(kHasBeenDeleted);
 }
 
@@ -196,24 +200,34 @@ void IndexedDBDispatcher::CursorDestroyed(int32_t ipc_cursor_id) {
 
 void IndexedDBDispatcher::RegisterMojoOwnedCallbacks(
     IndexedDBCallbacksImpl::InternalState* callbacks) {
-  mojo_owned_callback_state_.insert(callbacks);
+  mojo_owned_callback_state_[callbacks] = base::WrapUnique(callbacks);
 }
 
 void IndexedDBDispatcher::UnregisterMojoOwnedCallbacks(
     IndexedDBCallbacksImpl::InternalState* callbacks) {
-  DCHECK(base::ContainsValue(mojo_owned_callback_state_, callbacks));
-  mojo_owned_callback_state_.erase(callbacks);
+  if (in_destructor_)
+    return;
+
+  auto it = mojo_owned_callback_state_.find(callbacks);
+  DCHECK(it != mojo_owned_callback_state_.end());
+  it->second.release();
+  mojo_owned_callback_state_.erase(it);
 }
 
 void IndexedDBDispatcher::RegisterMojoOwnedDatabaseCallbacks(
     blink::WebIDBDatabaseCallbacks* callbacks) {
-  mojo_owned_database_callback_state_.insert(callbacks);
+  mojo_owned_database_callback_state_[callbacks] = base::WrapUnique(callbacks);
 }
 
 void IndexedDBDispatcher::UnregisterMojoOwnedDatabaseCallbacks(
     blink::WebIDBDatabaseCallbacks* callbacks) {
-  DCHECK(base::ContainsValue(mojo_owned_database_callback_state_, callbacks));
-  mojo_owned_database_callback_state_.erase(callbacks);
+  if (in_destructor_)
+    return;
+
+  auto it = mojo_owned_database_callback_state_.find(callbacks);
+  DCHECK(it != mojo_owned_database_callback_state_.end());
+  it->second.release();
+  mojo_owned_database_callback_state_.erase(it);
 }
 
 // Populate some WebIDBValue members (data & blob info) from the supplied