Data reduction proxy enabled/disabled UMA for all platforms

components/data_reduction_proxy/core/browser/data_reduction_proxy_settings.h

Index: components/data_reduction_proxy/core/browser/data_reduction_proxy_settings.h
diff --git a/components/data_reduction_proxy/core/browser/data_reduction_proxy_settings.h b/components/data_reduction_proxy/core/browser/data_reduction_proxy_settings.h
index c6d697458acde038a310216756790198aa0c42ac..a3de1d18cdecd9e1e9c06fb23b7cc1fa108d85c1 100644
--- a/components/data_reduction_proxy/core/browser/data_reduction_proxy_settings.h
+++ b/components/data_reduction_proxy/core/browser/data_reduction_proxy_settings.h
@@ -55,6 +55,16 @@ enum LoFiImplicitOptOutAction {
   LO_FI_OPT_OUT_ACTION_INDEX_BOUNDARY,
 };
 
+// Values of the UMA DataReductionProxy.EnabledState histogram.
+// This enum must remain synchronized with
+// DataReductionProxyEnabledState in
+// metrics/histograms/histograms.xml.
+enum DataReductionSettingsEnabledAction {
+  DATA_REDUCTION_SETTINGS_ACTION_OFF_TO_ON = 0,
+  DATA_REDUCTION_SETTINGS_ACTION_ON_TO_OFF,
+  DATA_REDUCTION_SETTINGS_ACTION_BOUNDARY,
+};
+
 // Central point for configuring the data reduction proxy.
 // This object lives on the UI thread and all of its methods are expected to
 // be called from there.
@@ -205,6 +215,11 @@ class DataReductionProxySettings : public DataReductionProxyServiceObserver {
   virtual void RecordStartupState(
       data_reduction_proxy::ProxyStartupState state);
 
+  // Virtualized for mocking. Records UMA whenever user toggles the
+  // ON/OFF in settings UI
+  virtual void RecordSettingsEnabledState(
+      data_reduction_proxy::DataReductionSettingsEnabledAction action);
+
  private:
   friend class DataReductionProxySettingsTestBase;
   friend class DataReductionProxySettingsTest;
@@ -236,6 +251,8 @@ class DataReductionProxySettings : public DataReductionProxyServiceObserver {
                            TestLoFiImplicitOptOutHistograms);
   FRIEND_TEST_ALL_PREFIXES(DataReductionProxySettingsTest,
                            TestLoFiSessionStateHistograms);
+  FRIEND_TEST_ALL_PREFIXES(DataReductionProxySettingsTest,

[sclittle, 2015/10/09 20:52:48]

I don't think you need this FRIEND_TEST_ALL_PREFIXES, since your test isn't
trying to call any protected or private methods of DataReductionProxySettings.

[Raj, 2015/10/10 01:51:47]

TestSettingsEnabledStateHistograms() calls settings_->InitPrefMembers() which
requires it to be friend

+                           TestSettingsEnabledStateHistograms);
 
   // Override of DataReductionProxyService::Observer.
   void OnServiceInitialized() override;