Oilpan: Prepare to move DatabaseThread and SQLTransactionCoordinator to Oilpan heap.

Source/modules/webdatabase/DatabaseThread.cpp

Index: Source/modules/webdatabase/DatabaseThread.cpp
diff --git a/Source/modules/webdatabase/DatabaseThread.cpp b/Source/modules/webdatabase/DatabaseThread.cpp
index b4afdaba1fcf1cb6152ced89bab69225bcc319dd..055808959d466c23552cde96a854418b5022075b 100644
--- a/Source/modules/webdatabase/DatabaseThread.cpp
+++ b/Source/modules/webdatabase/DatabaseThread.cpp
@@ -42,7 +42,7 @@ namespace WebCore {
 
 DatabaseThread::DatabaseThread()
     : m_transactionClient(adoptPtr(new SQLTransactionClient()))
-    , m_transactionCoordinator(adoptPtr(new SQLTransactionCoordinator()))
+    , m_transactionCoordinator(adoptPtrWillBeNoop(new SQLTransactionCoordinator()))
     , m_cleanupSync(0)
     , m_terminationRequested(false)
 {
@@ -60,6 +60,12 @@ DatabaseThread::~DatabaseThread()
     m_thread.clear();
 }
 
+void DatabaseThread::trace(Visitor* visitor)
+{
+    visitor->trace(m_openDatabaseSet);
+    visitor->trace(m_transactionCoordinator);
+}
+
 void DatabaseThread::start()
 {
     if (m_thread)