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

src/scopeinfo.cc

Index: src/scopeinfo.cc
diff --git a/src/scopeinfo.cc b/src/scopeinfo.cc
index c0b2c4c8e6cf4799ccf7a5257cea87ba989f1c31..5ec2527cc79d14290106b38c1e08772350d1b56d 100644
--- a/src/scopeinfo.cc
+++ b/src/scopeinfo.cc
@@ -362,6 +362,29 @@ int ScopeInfo::FunctionContextSlotIndex(String* name, VariableMode* mode) {
 }
 
 
+bool ScopeInfo::CopyContextLocalsToScopeObject(
+    Isolate* isolate,
+    Handle<Context> context,
+    Handle<JSObject> scope_object) {
+  // Fill all context locals to the context extension.
+  int start = ContextLocalNameEntriesIndex();
+  int end = start + ContextLocalCount();
+  for (int i = start; i < end; ++i) {
+    int context_index = Context::MIN_CONTEXT_SLOTS + i - start;
+    RETURN_IF_EMPTY_HANDLE_VALUE(
+        isolate,
+        SetProperty(isolate,
+                    scope_object,
+                    Handle<String>(String::cast(get(i))),
+                    Handle<Object>(context->get(context_index), isolate),
+                    ::NONE,
+                    kNonStrictMode),
+        false);
+  }
+  return true;
+}
+
+
 int ScopeInfo::ParameterEntriesIndex() {
   ASSERT(length() > 0);
   return kVariablePartIndex;