Split ExtensionSystem interface from ExtensionSystemImpl implementation, part 1.

chrome/browser/accessibility/accessibility_extension_api.cc

 // Copyright (c) 2012 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.
 
 #include "chrome/browser/accessibility/accessibility_extension_api.h"
 
 #include "base/json/json_writer.h"
 #include "base/strings/string_number_conversions.h"
 #include "base/values.h"
 #include "chrome/browser/accessibility/accessibility_extension_api_constants.h"
 #include "chrome/browser/extensions/api/tabs/tabs_constants.h"
 #include "chrome/browser/extensions/extension_host.h"
 #include "chrome/browser/extensions/extension_service.h"
-#include "chrome/browser/extensions/extension_system.h"
 #include "chrome/browser/extensions/extension_tab_util.h"
 #include "chrome/browser/infobars/confirm_infobar_delegate.h"
 #include "chrome/browser/infobars/infobar.h"
 #include "chrome/browser/infobars/infobar_service.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/common/extensions/api/experimental_accessibility.h"
 #include "content/public/browser/browser_accessibility_state.h"
 #include "extensions/browser/event_router.h"
+#include "extensions/browser/extension_system.h"
 #include "extensions/browser/lazy_background_task_queue.h"
 #include "extensions/common/error_utils.h"
 #include "extensions/common/manifest_handlers/background_info.h"
 
 namespace keys = extension_accessibility_api_constants;
 namespace experimental_accessibility =
     extensions::api::experimental_accessibility;
 
 // Returns the AccessibilityControlInfo serialized into a JSON string,
 // consisting of an array of a single object of type AccessibilityObject,
@@ skipping 251 matching lines @@
       const base::string16 message_text =
           confirm_infobar_delegate->GetMessageText();
       alert_value->SetString(keys::kMessageKey, message_text);
       alerts_value->Append(alert_value);
     }
   }
 
   SetResult(alerts_value);
   return true;
 }