Make HTMLImportTreeNode own the whole import tree.

Source/core/html/imports/HTMLImportsController.h

Index: Source/core/html/imports/HTMLImportsController.h
diff --git a/Source/core/html/imports/HTMLImportsController.h b/Source/core/html/imports/HTMLImportsController.h
index 2886001e002130f7d319d13e23da9a35b727d038..297cce49382e175a4a3a907c577275b0c521c577 100644
--- a/Source/core/html/imports/HTMLImportsController.h
+++ b/Source/core/html/imports/HTMLImportsController.h
@@ -73,15 +73,12 @@ public:
     LocalFrame* frame() const;
     Document* master() const { return m_master; }
 
-
     HTMLImportLoader* createLoader();
 
     size_t loaderCount() const { return m_loaders.size(); }
     HTMLImportLoader* loaderAt(size_t i) const { return m_loaders[i].get(); }
     HTMLImportLoader* loaderFor(const Document&) const;
 
-    HTMLImportChild* findLinkFor(const KURL&) const;
-
 private:
     HTMLImportChild* createChild(const KURL&, HTMLImportLoader*, HTMLImport* parent, HTMLImportChildClient*);
     void clear();
@@ -90,10 +87,6 @@ private:
 
     OwnPtr<HTMLImportTreeRoot> m_root;
 
-    // List of import which has been loaded or being loaded.
-    typedef Vector<OwnPtr<HTMLImportChild> > ImportList;
-    ImportList m_imports;
-
     typedef Vector<RefPtr<HTMLImportLoader> > LoaderList;
     LoaderList m_loaders;
 };