Move adding Lo-Fi directives from DRPRequestOptions to ContentLoFiDecider

components/data_reduction_proxy/content/browser/content_lofi_decider.cc

 // 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.
 
 #include "components/data_reduction_proxy/content/browser/content_lofi_decider.h"
 
+#include <string>
+
+#include "components/data_reduction_proxy/core/common/data_reduction_proxy_headers.h"
+#include "components/data_reduction_proxy/core/common/data_reduction_proxy_params.h"
 #include "content/public/browser/resource_request_info.h"
+#include "net/http/http_request_headers.h"
 
 namespace data_reduction_proxy {
 
 ContentLoFiDecider::ContentLoFiDecider() {}
 
 ContentLoFiDecider::~ContentLoFiDecider() {}
 
 bool ContentLoFiDecider::IsUsingLoFiMode(const net::URLRequest& request) const {
   const content::ResourceRequestInfo* request_info =
       content::ResourceRequestInfo::ForRequest(&request);
+  // The Lo-Fi directive should not be added for users in the Lo-Fi field
+  // trial "Control" group. Check that the user is in a group that should

[tbansal1, 2015/11/23 20:39:52]

s/should/can?

[megjablon, 2015/11/23 20:53:55]

Done.

+  // get "q=low".
+  bool lofi_enabled_via_flag_or_field_trial =
+      params::IsLoFiOnViaFlags() || params::IsIncludedInLoFiEnabledFieldTrial();
   if (request_info)
-    return request_info->IsUsingLoFi();
+    return request_info->IsUsingLoFi() && lofi_enabled_via_flag_or_field_trial;

[tbansal1, 2015/11/23 20:39:52]

Is it possible that "request_info->IsUsingLoFi()" is true even though
|lofi_enabled_via_flag_or_field_trial| is false?
Please add a comment when this may happen.

[megjablon, 2015/11/23 20:53:55]

Done.

   return false;
 }
 
+bool ContentLoFiDecider::MaybeAddLoFiDirectiveToHeaders(
+    const net::URLRequest& request,
+    net::HttpRequestHeaders* headers) const {
+  const content::ResourceRequestInfo* request_info =
+      content::ResourceRequestInfo::ForRequest(&request);
+
+  if (request_info) {

[tbansal1, 2015/11/23 20:39:52]

nit to reduce indentation:
if(!request_info)
  return false;

[megjablon, 2015/11/23 20:53:55]

Done.

+    // The Lo-Fi directive should not be added for users in the Lo-Fi field
+    // trial "Control" group. Check that the user is in a group that should
+    // get "q=low".
+    bool lofi_enabled_via_flag_or_field_trial =
+        params::IsLoFiOnViaFlags() ||
+        params::IsIncludedInLoFiEnabledFieldTrial();
+
+    std::string header_value;
+
+    // User is using Lo-Fi and not part of the "Control" group.
+    if (request_info->IsUsingLoFi() && lofi_enabled_via_flag_or_field_trial) {
+      if (headers->HasHeader(chrome_proxy_header())) {
+        headers->GetHeader(chrome_proxy_header(), &header_value);
+        headers->RemoveHeader(chrome_proxy_header());
+        header_value += ", ";
+      }
+      header_value += chrome_proxy_lo_fi_directive();
+      headers->SetHeader(chrome_proxy_header(), header_value);
+      return true;
+    }
+
+    // User is part of Lo-Fi active control experiment.
+    if (request_info->IsUsingLoFi() &&
+        params::IsIncludedInLoFiControlFieldTrial()) {
+      if (headers->HasHeader(chrome_proxy_header())) {
+        headers->GetHeader(chrome_proxy_header(), &header_value);
+        headers->RemoveHeader(chrome_proxy_header());
+        header_value += ", ";
+      }
+      header_value += chrome_proxy_lo_fi_experiment_directive();
+      headers->SetHeader(chrome_proxy_header(), header_value);
+    }
+  }
+
+  return false;
+}
+
 }  // namespace data_reduction_proxy