Implemented declarative redirects to transparent image and empty document.

chrome/browser/extensions/api/declarative_webrequest/webrequest_constants.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/extensions/api/declarative_webrequest/webrequest_constants.h"
 
 namespace extensions {
 namespace declarative_webrequest_constants {
 
 // Signals to which WebRequestRulesRegistries are registered.
 const char kOnRequest[] = "declarativeWebRequest.onRequest";
 
 // Keys of dictionaries.
 const char kInstanceTypeKey[] = "instanceType";
 const char kRedirectUrlKey[] = "redirectUrl";
 const char kResourceTypeKey[] = "resourceType";
 const char kUrlKey[] = "url";
 
 // Values of dictionaries, in particular instance types
 const char kCancelRequestType[] = "declarativeWebRequest.CancelRequest";
 const char kRedirectRequestType[] = "declarativeWebRequest.RedirectRequest";
+const char kRedirectToEmptyDocumentType[] =
+    "declarativeWebRequest.RedirectToEmptyDocument";
+const char kRedirectToTransparentImageType[] =
+    "declarativeWebRequest.RedirectToTransparentImage";
 const char kRequestMatcherType[] = "declarativeWebRequest.RequestMatcher";
 
 }  // namespace declarative_webrequest_constants
 }  // namespace extensions