Oilpan: move InspectorOverlay to the heap.

Source/core/inspector/InspectorController.cpp

Index: Source/core/inspector/InspectorController.cpp
diff --git a/Source/core/inspector/InspectorController.cpp b/Source/core/inspector/InspectorController.cpp
index a6e7c70cc449ad743b91dda3684d7956a07104cf..84d8a46b7fafbca9d381dec2d6b15e56e747b150 100644
--- a/Source/core/inspector/InspectorController.cpp
+++ b/Source/core/inspector/InspectorController.cpp
@@ -137,6 +137,7 @@ void InspectorController::trace(Visitor* visitor)
     visitor->trace(m_instrumentingAgents);
     visitor->trace(m_injectedScriptManager);
     visitor->trace(m_state);
+    visitor->trace(m_overlay);
     visitor->trace(m_domAgent);
     visitor->trace(m_animationAgent);
     visitor->trace(m_pageAgent);
@@ -288,7 +289,7 @@ void InspectorController::disconnectFrontend()
 
     m_inspectorFrontend.clear();
 
-    // relese overlay page resources
+    // Release overlay page resources
     m_overlay->freePage();
     InspectorInstrumentation::frontendDeleted();
     InspectorInstrumentation::unregisterInstrumentingAgents(m_instrumentingAgents.get());