Remove ActiveDOMObject::willStop, and introduce WorkerGlobalScope::TerminationObserver.

Source/modules/webdatabase/DatabaseContext.cpp

Index: Source/modules/webdatabase/DatabaseContext.cpp
diff --git a/Source/modules/webdatabase/DatabaseContext.cpp b/Source/modules/webdatabase/DatabaseContext.cpp
index 5ff09d800b9396717989dfd74c75865ea4cf1a84..a9828bc84b95f4576ccf98e5b70b6a7a4e2f30bc 100644
--- a/Source/modules/webdatabase/DatabaseContext.cpp
+++ b/Source/modules/webdatabase/DatabaseContext.cpp
@@ -105,6 +105,8 @@ DatabaseContext::DatabaseContext(ExecutionContext* context)
     // For debug accounting only. We must do this before we register the
     // instance. The assertions assume this.
     DatabaseManager::manager().didConstructDatabaseContext();
+    if (context->isWorkerGlobalScope())
+        toWorkerGlobalScope(context)->registerTerminationObserver(this);
 }
 
 DatabaseContext::~DatabaseContext()
@@ -129,11 +131,13 @@ void DatabaseContext::contextDestroyed()
 {
     RefPtrWillBeRawPtr<DatabaseContext> protector(this);
     stopDatabases();
+    if (executionContext()->isWorkerGlobalScope())
+        toWorkerGlobalScope(executionContext())->unregisterTerminationObserver(this);
     DatabaseManager::manager().unregisterDatabaseContext(this);
     ActiveDOMObject::contextDestroyed();
 }
 
-void DatabaseContext::willStop()
+void DatabaseContext::wasRequestedToTerminate()
 {
     DatabaseManager::manager().interruptAllDatabasesForContext(this);
 }