Move adding Lo-Fi directives from DRPRequestOptions to ContentLoFiDecider

components/data_reduction_proxy/core/common/lofi_decider.h

Index: components/data_reduction_proxy/core/common/lofi_decider.h
diff --git a/components/data_reduction_proxy/core/common/lofi_decider.h b/components/data_reduction_proxy/core/common/lofi_decider.h
index dfe484c6681a726ec5fa5e629013cbbc71fc7934..727b87b59927fe34b9e8bf159cdd1a54dd2aff48 100644
--- a/components/data_reduction_proxy/core/common/lofi_decider.h
+++ b/components/data_reduction_proxy/core/common/lofi_decider.h
@@ -8,6 +8,10 @@
 #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
@@ -17,9 +21,16 @@ class LoFiDecider {
   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