[DevTools] Fix leak in InspectorDatabaseAgent.

third_party/WebKit/Source/modules/webdatabase/InspectorDatabaseAgent.cpp

 /*
  * Copyright (C) 2010 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  *
  * 1.  Redistributions of source code must retain the above copyright
  *     notice, this list of conditions and the following disclaimer.
  * 2.  Redistributions in binary form must reproduce the above copyright
@@ skipping 241 matching lines @@
     , m_enabled(false)
 {
     DatabaseClient::fromPage(page)->setInspectorAgent(this);
     DatabaseTracker::tracker().forEachOpenDatabaseInPage(m_page, bind<blink::Database*>(&InspectorDatabaseAgent::registerDatabaseOnCreation, this));
 }
 
 InspectorDatabaseAgent::~InspectorDatabaseAgent()
 {
 }
 
+void InspectorDatabaseAgent::discardAgent()
+{
+    if (DatabaseClient* client = DatabaseClient::fromPage(m_page))
+        client->setInspectorAgent(nullptr);
+}
+
 void InspectorDatabaseAgent::enable(ErrorString*)
 {
     if (m_enabled)
         return;
     m_enabled = true;
     m_state->setBoolean(DatabaseAgentState::databaseAgentEnabled, m_enabled);
 
     DatabaseResourcesHeapMap::iterator databasesEnd = m_resources.end();
     for (DatabaseResourcesHeapMap::iterator it = m_resources.begin(); it != databasesEnd; ++it)
         it->value->bind(frontend());
@@ skipping 70 matching lines @@
 }
 
 DEFINE_TRACE(InspectorDatabaseAgent)
 {
     visitor->trace(m_page);
     visitor->trace(m_resources);
     InspectorBaseAgent::trace(visitor);
 }
 
 } // namespace blink