Update data reduction proxy statistics prefs less often on desktop

android_webview/browser/net/aw_url_request_context_getter.cc

Index: android_webview/browser/net/aw_url_request_context_getter.cc
diff --git a/android_webview/browser/net/aw_url_request_context_getter.cc b/android_webview/browser/net/aw_url_request_context_getter.cc
index 2e7d41240cbd03616d3801a7357627405e9c32b5..3b3d9c676a3dd1ed7972724366f4e4c577a4744f 100644
--- a/android_webview/browser/net/aw_url_request_context_getter.cc
+++ b/android_webview/browser/net/aw_url_request_context_getter.cc
@@ -239,6 +239,9 @@ void AwURLRequestContextGetter::InitializeURLRequestContext() {
           data_reduction_proxy_settings->params(),
           BrowserThread::GetMessageLoopProxyForThread(BrowserThread::IO)));
 
+  // Compression statistics are not gathered for WebView, so
+  // DataReductionProxyStatisticsPrefs is not instantiated and passed to the
+  // network delegate.
   aw_network_delegate->set_data_reduction_proxy_params(
       data_reduction_proxy_settings->params());
   aw_network_delegate->set_data_reduction_proxy_auth_request_handler(