[Extensions] Isolate ExtensionFunction results_ and error_

chrome/browser/extensions/api/input_ime/input_ime_api_nonchromeos.cc

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // This file is for non-chromeos (win & linux) functions, such as
 // chrome.input.ime.activate, chrome.input.ime.createWindow and
 // chrome.input.ime.onSelectionChanged.
 // TODO(azurewei): May refactor the code structure by using delegate or
 // redesign the API to remove this platform-specific file in the future.
 
@@ skipping 337 matching lines @@
     bounds.set_y(options.bounds->top);
     bounds.set_width(options.bounds->width);
     bounds.set_height(options.bounds->height);
   }
 
   InputMethodEngine* engine =
       GetActiveEngine(browser_context(), extension_id());
   if (!engine)
     return RespondNow(Error(kErrorNoActiveEngine));
 
+  std::string error;
   int frame_id = engine->CreateImeWindow(
       extension(), render_frame_host(),
       options.url.get() ? *options.url : url::kAboutBlankURL,
       options.window_type == input_ime::WINDOW_TYPE_FOLLOWCURSOR
           ? ui::ImeWindow::FOLLOW_CURSOR
           : ui::ImeWindow::NORMAL,
-      bounds, &error_);
+      bounds, &error);
   if (!frame_id)
-    return RespondNow(Error(error_));
+    return RespondNow(Error(error));
 
   std::unique_ptr<base::DictionaryValue> result(new base::DictionaryValue());
   result->Set("frameId", new base::FundamentalValue(frame_id));
 
   return RespondNow(OneArgument(std::move(result)));
 }
 
 ExtensionFunction::ResponseAction InputImeShowWindowFunction::Run() {
   if (!IsInputImeEnabled())
     return RespondNow(Error(kErrorAPIDisabled));
@@ skipping 20 matching lines @@
     return RespondNow(Error(kErrorNoActiveEngine));
 
   std::unique_ptr<api::input_ime::HideWindow::Params> params(
       api::input_ime::HideWindow::Params::Create(*args_));
   EXTENSION_FUNCTION_VALIDATE(params.get());
   engine->HideImeWindow(params->window_id);
   return RespondNow(NoArguments());
 }
 
 }  // namespace extensions