Factor DRP PreviewsState logic out of content

components/data_reduction_proxy/core/common/data_reduction_proxy_headers.h

 // Copyright 2014 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.
 
 #ifndef COMPONENTS_DATA_REDUCTION_PROXY_CORE_COMMON_DATA_REDUCTION_PROXY_HEADERS_H_
 #define COMPONENTS_DATA_REDUCTION_PROXY_CORE_COMMON_DATA_REDUCTION_PROXY_HEADERS_H_
 
 #include <string>
 #include <vector>
 
@@ skipping 77 matching lines @@
 const char* empty_image_directive();
 
 // Gets the directive used by data reduction proxy Lite-Page requests
 // and responses.
 const char* lite_page_directive();
 
 // Gets the directive used by the data reduction proxy to request
 // compressed video.
 const char* compressed_video_directive();
 
+// Gets the directive used by the data reduction proxy to tell the client to use
+// a specific page policy.
+const char* page_policies_directive();
+
 // Gets the Chrome-Proxy directive used by data reduction proxy lite page
 // preview requests and responses.
 const char* chrome_proxy_lite_page_directive();
 
 // Gets the Chrome-Proxy experiment ("exp") value to force a lite page preview
 // for requests that accept lite pages.
 const char* chrome_proxy_experiment_force_lite_page();
 
 // Gets the Chrome-Proxy experiment ("exp") value to force an empty image
 // preview for requests that enable server provided previews.
@@ skipping 77 matching lines @@
     const net::HttpResponseHeaders* headers,
     std::string* content_length_fingerprint);
 
 // Returns values of the Chrome-Proxy header, but with its fingerprint removed.
 void GetDataReductionProxyHeaderWithFingerprintRemoved(
     const net::HttpResponseHeaders* headers,
     std::vector<std::string>* values);
 
 }  // namespace data_reduction_proxy
 #endif  // COMPONENTS_DATA_REDUCTION_PROXY_CORE_COMMON_DATA_REDUCTION_PROXY_HEADERS_H_