Move adding Lo-Fi directives from DRPRequestOptions to ContentLoFiDecider

components/data_reduction_proxy/core/common/lofi_decider.h

 // 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.
 
 #ifndef COMPONENTS_DATA_REDUCTION_PROXY_CORE_BROWSER_LOFI_DECIDER_H_
 #define COMPONENTS_DATA_REDUCTION_PROXY_CORE_BROWSER_LOFI_DECIDER_H_
 
 #include "base/macros.h"
 #include "net/url_request/url_request.h"
 
+namespace net {
+class HttpRequestHeaders;
+}
+
 namespace data_reduction_proxy {
 
 // Interface to determine if a request should be made for a low fidelity version
 // of the resource.
 class LoFiDecider {
  public:
   virtual ~LoFiDecider() {}
 
   // Returns true when Lo-Fi mode is on for the given |request|. This means the
-  // Lo-Fi header should be added to the given request, unless the user is in
-  // in the Lo-Fi control group.
+  // Lo-Fi header should be added to the given request.
   virtual bool IsUsingLoFiMode(const net::URLRequest& request) const = 0;
+
+  // Returns true when Lo-Fi mode is on for the given |request|. If the
+  // |request| is using Lo-Fi mode, adds the "q=low" directive to the |headers|.
+  // If the user is in the experiment control group and Lo-Fi is on, adds the
+  // experiment directive "exp=lofi_active_control".
+  virtual bool MaybeAddLoFiDirectiveToHeaders(
+      const net::URLRequest& request,
+      net::HttpRequestHeaders* headers) const = 0;
 };
 
 }  // namespace data_reduction_proxy
 
 #endif  // COMPONENTS_DATA_REDUCTION_PROXY_CORE_BROWSER_LOFI_DECIDER_H_