Revert of Enable DRP config service by default

components/data_reduction_proxy/core/common/data_reduction_proxy_params.cc

Index: components/data_reduction_proxy/core/common/data_reduction_proxy_params.cc
diff --git a/components/data_reduction_proxy/core/common/data_reduction_proxy_params.cc b/components/data_reduction_proxy/core/common/data_reduction_proxy_params.cc
index eaf326aa6c1449e86fb81e16a2dd378dee1f022b..05ee6890c7de2a9bbe32f348351d2ff02391bf13 100644
--- a/components/data_reduction_proxy/core/common/data_reduction_proxy_params.cc
+++ b/components/data_reduction_proxy/core/common/data_reduction_proxy_params.cc
@@ -47,6 +47,9 @@
 const char kLoFiFieldTrial[] = "DataCompressionProxyLoFi";
 const char kLoFiFlagFieldTrial[] = "DataCompressionProxyLoFiFlag";
 
+const char kConfigServiceFieldTrial[] = "DataReductionProxyConfigService";
+const char kConfigServiceURLParam[] = "url";
+
 const char kTrustedSpdyProxyFieldTrialName[] = "DataReductionTrustedSpdyProxy";
 
 // Default URL for retrieving the Data Reduction Proxy configuration.
@@ -183,10 +186,18 @@
          (FieldTrialList::FindFullName(kDevRolloutFieldTrial) == kEnabled);
 }
 
+std::string GetClientConfigFieldTrialName() {
+  return kConfigServiceFieldTrial;
+}
+
 bool IsConfigClientEnabled() {
-  // TODO(tbansal): crbug.com/597768 Remove the data reduction proxy deprecated
-  // code which was used when config client is not enabled.
-  return true;
+  std::string group_value =
+      base::FieldTrialList::FindFullName(kConfigServiceFieldTrial);
+  base::StringPiece group = group_value;
+  return base::CommandLine::ForCurrentProcess()->HasSwitch(
+             data_reduction_proxy::switches::
+                 kEnableDataReductionProxyConfigClient) ||
+         group.starts_with(kEnabled);
 }
 
 GURL GetConfigServiceURL() {
@@ -195,6 +206,11 @@
   if (command_line->HasSwitch(switches::kDataReductionProxyConfigURL)) {
     url = command_line->GetSwitchValueASCII(
         switches::kDataReductionProxyConfigURL);
+  }
+
+  if (url.empty()) {
+    url = variations::GetVariationParamValue(kConfigServiceFieldTrial,
+                                             kConfigServiceURLParam);
   }
 
   if (url.empty())