[oilpan] Completely move HTMLFormControlElement's hierarchy to the managed heap

Source/core/inspector/InspectorDOMAgent.cpp

Index: Source/core/inspector/InspectorDOMAgent.cpp
diff --git a/Source/core/inspector/InspectorDOMAgent.cpp b/Source/core/inspector/InspectorDOMAgent.cpp
index a2416f15d12cc8ed74f8facf388f1dfc3d7f9f0a..3c4e22a525d787a248ddcc7e83e4c65312868dd6 100644
--- a/Source/core/inspector/InspectorDOMAgent.cpp
+++ b/Source/core/inspector/InspectorDOMAgent.cpp
@@ -1282,7 +1282,7 @@ void InspectorDOMAgent::setFileInputFiles(ErrorString* errorString, int nodeId,
     Node* node = assertNode(errorString, nodeId);
     if (!node)
         return;
-    HTMLInputElement* element = node->toInputElement();
+    Handle<HTMLInputElement> element = node->toInputElement();
     if (!element || !element->isFileUpload()) {
         *errorString = "Node is not a file input element";
         return;