Do not look for the slot in the ScopeInfo's global range when it's not necessary.

src/debug/debug-scopes.cc

 // Copyright 2015 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/debug/debug-scopes.h"
 
 #include "src/debug/debug.h"
 #include "src/frames-inl.h"
 #include "src/globals.h"
 #include "src/isolate-inl.h"
@@ skipping 543 matching lines @@
 
 // Set the context local variable value.
 bool ScopeIterator::SetContextLocalValue(Handle<ScopeInfo> scope_info,
                                          Handle<Context> context,
                                          Handle<String> variable_name,
                                          Handle<Object> new_value) {
   for (int i = 0; i < scope_info->ContextLocalCount(); i++) {
     Handle<String> next_name(scope_info->ContextLocalName(i));
     if (String::Equals(variable_name, next_name)) {
       VariableMode mode;
-      VariableLocation location;
       InitializationFlag init_flag;
       MaybeAssignedFlag maybe_assigned_flag;
-      int context_index =
-          ScopeInfo::ContextSlotIndex(scope_info, next_name, &mode, &location,
-                                      &init_flag, &maybe_assigned_flag);
+      int context_index = ScopeInfo::ContextSlotIndex(
+          scope_info, next_name, &mode, &init_flag, &maybe_assigned_flag);
       context->set(context_index, *new_value);
       return true;
     }
   }
 
   return false;
 }
 
 
 bool ScopeIterator::SetLocalVariableValue(Handle<String> variable_name,
@@ skipping 201 matching lines @@
         isolate_, value, Object::GetPropertyOrElement(extension, key), false);
     RETURN_ON_EXCEPTION_VALUE(
         isolate_, JSObject::SetOwnPropertyIgnoreAttributes(
             scope_object, key, value, NONE), false);
   }
   return true;
 }
 
 }  // namespace internal
 }  // namespace v8