Add WebContents source to methods in WebContentsDelegate

chrome/browser/prerender/prerender_manager.cc

Index: chrome/browser/prerender/prerender_manager.cc
diff --git a/chrome/browser/prerender/prerender_manager.cc b/chrome/browser/prerender/prerender_manager.cc
index cfdeb2b7e3275303e05fdd9f60131b2f160311d4..146af7a6f41899d8108159e01af94fa970050506 100644
--- a/chrome/browser/prerender/prerender_manager.cc
+++ b/chrome/browser/prerender/prerender_manager.cc
@@ -191,7 +191,7 @@ class PrerenderManager::OnCloseWebContentsDeleter
     ScheduleWebContentsForDeletion(false);
   }
 
-  bool ShouldSuppressDialogs() override {
+  bool ShouldSuppressDialogs(WebContents* source) override {

[davidben, 2014/11/07 19:08:26]

Nit: May as well add a
  DCHECK_EQ(tab_, source);

as with the others.

     // Use this as a proxy for getting statistics on how often we fail to honor
     // the beforeunload event.
     suppressed_dialog_ = true;