Add condition attribute for MIME media types from Content-Type header.

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 kContentTypeKey[] = "contentType";
 const char kFromKey[] = "from";
 const char kInstanceTypeKey[] = "instanceType";
 const char kLowerPriorityThanKey[] = "lowerPriorityThan";
 const char kNameKey[] = "name";
 const char kRedirectUrlKey[] = "redirectUrl";
 const char kResourceTypeKey[] = "resourceType";
 const char kToKey[] = "to";
 const char kUrlKey[] = "url";
 const char kValueKey[] = "value";
 
@@ skipping 10 matching lines @@
 const char kRedirectToTransparentImageType[] =
     "declarativeWebRequest.RedirectToTransparentImage";
 const char kRemoveRequestHeaderType[] =
     "declarativeWebRequest.RemoveRequestHeader";
 const char kRemoveResponseHeaderType[] =
     "declarativeWebRequest.RemoveResponseHeader";
 const char kRequestMatcherType[] = "declarativeWebRequest.RequestMatcher";
 const char kSetRequestHeaderType[] = "declarativeWebRequest.SetRequestHeader";
 }  // namespace declarative_webrequest_constants
 }  // namespace extensions