Oilpan: Prepare moving InspectorFrontendHost to Oilpan

Source/core/inspector/InspectorFrontendHost.cpp

Index: Source/core/inspector/InspectorFrontendHost.cpp
diff --git a/Source/core/inspector/InspectorFrontendHost.cpp b/Source/core/inspector/InspectorFrontendHost.cpp
index c71023efa395fee84a84b09d86acb7541a39bba2..ec9c9ab28a63ead82c1c4f06925cdef61b92adf9 100644
--- a/Source/core/inspector/InspectorFrontendHost.cpp
+++ b/Source/core/inspector/InspectorFrontendHost.cpp
@@ -131,12 +131,17 @@ InspectorFrontendHost::~InspectorFrontendHost()
     ASSERT(!m_client);
 }
 
+void InspectorFrontendHost::trace(Visitor* visitor)
+{
+    visitor->trace(m_frontendPage);
+}
+
 void InspectorFrontendHost::disconnectClient()
 {
     m_client = 0;
     if (m_menuProvider)
         m_menuProvider->disconnect();
-    m_frontendPage = 0;
+    m_frontendPage = nullptr;
 }
 
 void InspectorFrontendHost::setZoomFactor(float zoom)