Remove unused DataReductionProxy code

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 fefe4c358aa9c532cf2298361bd57c64e2bbbe33..5a86b16c09e6bcbb5dd14965cc1893fb36e1b177 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
@@ -16,7 +16,6 @@
 #include "components/data_reduction_proxy/core/browser/data_reduction_proxy_config_service_client.h"
 #include "components/data_reduction_proxy/core/browser/data_reduction_proxy_configurator.h"
 #include "components/data_reduction_proxy/core/browser/data_reduction_proxy_delegate.h"
-#include "components/data_reduction_proxy/core/browser/data_reduction_proxy_experiments_stats.h"
 #include "components/data_reduction_proxy/core/browser/data_reduction_proxy_interceptor.h"
 #include "components/data_reduction_proxy/core/browser/data_reduction_proxy_mutable_config_values.h"
 #include "components/data_reduction_proxy/core/browser/data_reduction_proxy_network_delegate.h"
@@ -152,11 +151,6 @@ DataReductionProxyIOData::DataReductionProxyIOData(
 
   proxy_delegate_.reset(
       new DataReductionProxyDelegate(request_options_.get(), config_.get()));
-  // It is safe to use base::Unretained here, since it gets executed
-  // synchronously on the IO thread, and |this| outlives the caller (since the
-  // caller is owned by |this|.
-  experiments_stats_.reset(new DataReductionProxyExperimentsStats(base::Bind(
-      &DataReductionProxyIOData::SetInt64Pref, base::Unretained(this))));
  }
 
  DataReductionProxyIOData::DataReductionProxyIOData()
@@ -196,7 +190,6 @@ void DataReductionProxyIOData::InitializeOnIOThread() {
   config_->InitializeOnIOThread(basic_url_request_context_getter_.get());
   if (config_client_.get())
     config_client_->InitializeOnIOThread(url_request_context_getter_);
-  experiments_stats_->InitializeOnIOThread();
   if (ui_task_runner_->BelongsToCurrentThread()) {
     service_->SetIOData(weak_factory_.GetWeakPtr());
     return;
@@ -228,8 +221,8 @@ DataReductionProxyIOData::CreateNetworkDelegate(
   scoped_ptr<DataReductionProxyNetworkDelegate> network_delegate(
       new DataReductionProxyNetworkDelegate(
           std::move(wrapped_network_delegate), config_.get(),
-          request_options_.get(), configurator_.get(), experiments_stats_.get(),
-          net_log_, event_creator_.get()));
+          request_options_.get(), configurator_.get(), net_log_,
+          event_creator_.get()));
   if (track_proxy_bypass_statistics)
     network_delegate->InitIODataAndUMA(this, bypass_stats_.get());
   return network_delegate;