Debugger: ScopeMirror has N^2 algorithm when building closure mirrors.

src/objects.h

Index: src/objects.h
diff --git a/src/objects.h b/src/objects.h
index 600faeeafe56f25d2cb0da753ee19432fd78570b..e15eee346141985d42fc3a8f64c5cdaefc11de86 100644
--- a/src/objects.h
+++ b/src/objects.h
@@ -3559,6 +3559,13 @@ class ScopeInfo : public FixedArray {
   // must be a symbol (canonicalized).
   int FunctionContextSlotIndex(String* name, VariableMode* mode);
 
+
+  // Copies all the context locals into an object used to materialize a scope.
+  bool CopyContextLocalsToScopeObject(Isolate* isolate,
+                                      Handle<Context> context,
+                                      Handle<JSObject> scope_object);
+
+
   static Handle<ScopeInfo> Create(Scope* scope, Zone* zone);
 
   // Serializes empty scope info.