Make ScriptStreamer and dependents Oilpan friendly.

Source/bindings/core/v8/ScriptDebugServer.cpp

Index: Source/bindings/core/v8/ScriptDebugServer.cpp
diff --git a/Source/bindings/core/v8/ScriptDebugServer.cpp b/Source/bindings/core/v8/ScriptDebugServer.cpp
index 67f0680d5ee6d715692b6222b84959a24318056a..5472aeece516ba99b65a46b3f3e700334ad1476f 100644
--- a/Source/bindings/core/v8/ScriptDebugServer.cpp
+++ b/Source/bindings/core/v8/ScriptDebugServer.cpp
@@ -86,6 +86,10 @@ ScriptDebugServer::~ScriptDebugServer()
 {
 }
 
+void ScriptDebugServer::trace(Visitor* visitor)
+{
+}
+
 String ScriptDebugServer::setBreakpoint(const String& sourceID, const ScriptBreakpoint& scriptBreakpoint, int* actualLineNumber, int* actualColumnNumber, bool interstatementLocation)
 {
     v8::HandleScope scope(m_isolate);
@@ -743,9 +747,9 @@ void ScriptDebugServer::runScript(ScriptState* scriptState, const String& script
     }
 }
 
-PassOwnPtr<ScriptSourceCode> ScriptDebugServer::preprocess(LocalFrame*, const ScriptSourceCode&)
+Nullable<ScriptSourceCode> ScriptDebugServer::preprocess(LocalFrame*, const ScriptSourceCode&)
 {
-    return PassOwnPtr<ScriptSourceCode>();
+    return nullptr;
 }
 
 String ScriptDebugServer::preprocessEventListener(LocalFrame*, const String& source, const String& url, const String& functionName)