Add a way to send the resource percentage signal to the RC.

chrome/browser/page_load_metrics/page_load_metrics_initialize.h

Index: chrome/browser/page_load_metrics/page_load_metrics_initialize.h
diff --git a/chrome/browser/page_load_metrics/page_load_metrics_initialize.h b/chrome/browser/page_load_metrics/page_load_metrics_initialize.h
index 3df50d0dabae6110b662d36b5d6cac18ac4e4777..15653baeacd2e27fc144726fe5f8943fc93a342b 100644
--- a/chrome/browser/page_load_metrics/page_load_metrics_initialize.h
+++ b/chrome/browser/page_load_metrics/page_load_metrics_initialize.h
@@ -13,8 +13,10 @@ class WebContents;
 
 namespace chrome {
 
-void InitializePageLoadMetricsForWebContents(
-    content::WebContents* web_contents);
+// background_rendering is set to true when initializing the metrics for
+// a background render such as making an offline version of the page.
+void InitializePageLoadMetricsForWebContents(content::WebContents* web_contents,
+                                             bool background_rendering);
 
 }  // namespace chrome