Oilpan: fix build after r183810.

Source/bindings/core/v8/V8Initializer.cpp

Index: Source/bindings/core/v8/V8Initializer.cpp
diff --git a/Source/bindings/core/v8/V8Initializer.cpp b/Source/bindings/core/v8/V8Initializer.cpp
index 552f93ef7f021b4fa284135b312a91fe3a6cac7d..48430fd6fd8bcf7d64dc21be7d925cc2b5bc0a65 100644
--- a/Source/bindings/core/v8/V8Initializer.cpp
+++ b/Source/bindings/core/v8/V8Initializer.cpp
@@ -161,6 +161,7 @@ static void messageHandlerInMainThread(v8::Handle<v8::Message> message, v8::Hand
 namespace {
 
 class PromiseRejectMessage {
+    ALLOW_ONLY_INLINE_ALLOCATION();
 public:
     PromiseRejectMessage(const ScriptValue& promise, PassRefPtrWillBeRawPtr<ScriptCallStack> callStack)
         : m_promise(promise)
@@ -170,6 +171,11 @@ public:
 
     const ScriptValue m_promise;
     const RefPtrWillBeMember<ScriptCallStack> m_callStack;
+
+    void trace(Visitor* visitor)
+    {
+        visitor->trace(m_callStack);
+    }
 };
 
 } // namespace