Remove unused chrome_proxy_lo_fi_experiment_directive()

components/data_reduction_proxy/core/common/data_reduction_proxy_headers.h

Index: components/data_reduction_proxy/core/common/data_reduction_proxy_headers.h
diff --git a/components/data_reduction_proxy/core/common/data_reduction_proxy_headers.h b/components/data_reduction_proxy/core/common/data_reduction_proxy_headers.h
index 44f45280d160a571a8c35b8106ae8c34020154d9..093c6aba8bfe1ac2c2701639281b0c6a7dc46ad3 100644
--- a/components/data_reduction_proxy/core/common/data_reduction_proxy_headers.h
+++ b/components/data_reduction_proxy/core/common/data_reduction_proxy_headers.h
@@ -78,10 +78,6 @@ const char* chrome_proxy_lo_fi_directive();
 // requests and responses.
 const char* chrome_proxy_lo_fi_preview_directive();
 
-// Gets the Chrome-Proxy directive used by data reduction proxy Lo-Fi control
-// experiment requests.
-const char* chrome_proxy_lo_fi_experiment_directive();
-
 // Returns true if the Chrome-Proxy header is present and contains a bypass
 // delay. Sets |proxy_info->bypass_duration| to the specified delay if greater
 // than 0, and to 0 otherwise to indicate that the default proxy delay