Remove unused DataReductionProxy code

components/data_reduction_proxy/core/browser/data_reduction_proxy_io_data.h

Index: components/data_reduction_proxy/core/browser/data_reduction_proxy_io_data.h
diff --git a/components/data_reduction_proxy/core/browser/data_reduction_proxy_io_data.h b/components/data_reduction_proxy/core/browser/data_reduction_proxy_io_data.h
index de383f456cc5d0bda1185f12084e6468359708d5..fd1ec2058ebfbe6513c16993161335baf0980f8d 100644
--- a/components/data_reduction_proxy/core/browser/data_reduction_proxy_io_data.h
+++ b/components/data_reduction_proxy/core/browser/data_reduction_proxy_io_data.h
@@ -40,7 +40,6 @@ class DataReductionProxyConfig;
 class DataReductionProxyConfigServiceClient;
 class DataReductionProxyConfigurator;
 class DataReductionProxyEventCreator;
-class DataReductionProxyExperimentsStats;
 class DataReductionProxyService;
 
 // Contains and initializes all Data Reduction Proxy objects that operate on
@@ -141,10 +140,6 @@ class DataReductionProxyIOData : public DataReductionProxyEventStorageDelegate {
     return config_client_.get();
   }
 
-  DataReductionProxyExperimentsStats* experiments_stats() const {
-    return experiments_stats_.get();
-  }
-
   net::ProxyDelegate* proxy_delegate() const {
     return proxy_delegate_.get();
   }
@@ -249,9 +244,6 @@ class DataReductionProxyIOData : public DataReductionProxyEventStorageDelegate {
   // Requests new Data Reduction Proxy configurations from a remote service.
   scoped_ptr<DataReductionProxyConfigServiceClient> config_client_;
 
-  // Used to track stats for experiments.
-  scoped_ptr<DataReductionProxyExperimentsStats> experiments_stats_;
-
   // A net log.
   net::NetLog* net_log_;