Reset unreachable data reduction proxy message when data savings is toggled.

components/data_reduction_proxy/core/browser/data_reduction_proxy_io_data.cc

Index: components/data_reduction_proxy/core/browser/data_reduction_proxy_io_data.cc
diff --git a/components/data_reduction_proxy/core/browser/data_reduction_proxy_io_data.cc b/components/data_reduction_proxy/core/browser/data_reduction_proxy_io_data.cc
index 50a303cf7849faa3f32a8787cafbe931c7e41573..9de8165d996f098cb9b52e1917895ffd55b4ed93 100644
--- a/components/data_reduction_proxy/core/browser/data_reduction_proxy_io_data.cc
+++ b/components/data_reduction_proxy/core/browser/data_reduction_proxy_io_data.cc
@@ -215,12 +215,24 @@ DataReductionProxyIOData::CreateNetworkDelegate(
   return network_delegate.Pass();
 }
 
+// TODO(kundaji): Rename this method to something more descriptive.
+// Bug http://crbug/488190.
 void DataReductionProxyIOData::SetProxyPrefs(bool enabled,
                                              bool alternative_enabled,
                                              bool at_startup) {
   DCHECK(io_task_runner_->BelongsToCurrentThread());
+  DCHECK(url_request_context_getter_->GetURLRequestContext()->proxy_service());
   enabled_ = enabled;
   config_->SetProxyConfig(enabled, alternative_enabled, at_startup);
+
+  // If Data Saver is disabled, reset data reduction proxy state.
+  if (!enabled) {
+    net::ProxyService* proxy_service =
+        url_request_context_getter_->GetURLRequestContext()->proxy_service();
+    proxy_service->ClearBadProxiesCache();
+    bypass_stats_->ClearRequestCounts();
+    bypass_stats_->NotifyUnavailabilityIfChanged();
+  }
 }
 
 void DataReductionProxyIOData::UpdateContentLengths(