[PageLoadMetrics] Record bytes usage per page

chrome/browser/page_load_metrics/metrics_web_contents_observer.h

Index: chrome/browser/page_load_metrics/metrics_web_contents_observer.h
diff --git a/chrome/browser/page_load_metrics/metrics_web_contents_observer.h b/chrome/browser/page_load_metrics/metrics_web_contents_observer.h
index 02d4a80bb68a00010fb389bc134703434ef1104d..0bec17f8dc922225252479676f690273177a7027 100644
--- a/chrome/browser/page_load_metrics/metrics_web_contents_observer.h
+++ b/chrome/browser/page_load_metrics/metrics_web_contents_observer.h
@@ -72,7 +72,8 @@ class MetricsWebContentsObserver
   // A resource request completed on the IO thread.
   void OnRequestComplete(content::ResourceType resource_type,
                          bool was_cached,
-                         int net_error);
+                         int net_error,
+                         int64_t raw_body_bytes);
 
   // Flush any buffered metrics, as part of the metrics subsystem persisting
   // metrics as the application goes into the background. The application may be