Adding synthetic field trial for DataReductionProxyEnabled

chrome/browser/net/spdyproxy/data_reduction_proxy_chrome_settings.cc

Index: chrome/browser/net/spdyproxy/data_reduction_proxy_chrome_settings.cc
diff --git a/chrome/browser/net/spdyproxy/data_reduction_proxy_chrome_settings.cc b/chrome/browser/net/spdyproxy/data_reduction_proxy_chrome_settings.cc
index abdbe4bd60e623134369db81ff2249744cc6cdaf..c40cff2817c704ab820de0d5718c80bb44eb1f45 100644
--- a/chrome/browser/net/spdyproxy/data_reduction_proxy_chrome_settings.cc
+++ b/chrome/browser/net/spdyproxy/data_reduction_proxy_chrome_settings.cc
@@ -11,6 +11,8 @@
 #include "components/data_reduction_proxy/browser/data_reduction_proxy_configurator.h"
 #include "components/data_reduction_proxy/browser/data_reduction_proxy_params.h"
 #include "components/data_reduction_proxy/browser/data_reduction_proxy_settings.h"
+#include "components/metrics/metrics_service.h"
+#include "components/variations/metrics_util.h"
 
 using data_reduction_proxy::DataReductionProxyParams;
 using data_reduction_proxy::DataReductionProxySettings;
@@ -33,8 +35,20 @@ void DataReductionProxyChromeSettings::InitDataReductionProxySettings(
   DataReductionProxySettings::InitDataReductionProxySettings(
       prefs,
       g_browser_process->local_state(),
-      ProfileManager::GetActiveUserProfile()->GetRequestContext());
+      ProfileManager::GetActiveUserProfile()->GetRequestContext(),
+      base::Bind(&DataReductionProxyChromeSettings::RegisterSyntheticFieldTrial,
+                 base::Unretained(this)));
 
   SetDataReductionProxyAlternativeEnabled(
       DataReductionProxyParams::IsIncludedInAlternativeFieldTrial());
 }
+
+void DataReductionProxyChromeSettings::RegisterSyntheticFieldTrial(
+    bool data_reduction_proxy_enabled) {
+  if (g_browser_process->metrics_service()) {
+    SyntheticTrialGroup trial(
+        metrics::HashName("DataReductionProxyEnabled"),
+        metrics::HashName(data_reduction_proxy_enabled ? "true" : "false"));
+    g_browser_process->metrics_service()->RegisterSyntheticFieldTrial(trial);
+  }
+}