Pass result of blockage across content API when new tab blocked.

chrome/browser/ui/blocked_content/blocked_content_container.cc

Index: chrome/browser/ui/blocked_content/blocked_content_container.cc
===================================================================
--- chrome/browser/ui/blocked_content/blocked_content_container.cc	(revision 153532)
+++ chrome/browser/ui/blocked_content/blocked_content_container.cc	(working copy)
@@ -116,13 +116,14 @@
   return owner_->web_contents()->OpenURL(params);
 }
 
-void BlockedContentContainer::AddNewContents(WebContents* source,
+bool BlockedContentContainer::AddNewContents(WebContents* source,
                                              WebContents* new_contents,
                                              WindowOpenDisposition disposition,
                                              const gfx::Rect& initial_position,
                                              bool user_gesture) {
   owner_->web_contents()->AddNewContents(
       new_contents, disposition, initial_position, user_gesture);
+  return true;
 }
 
 void BlockedContentContainer::CloseContents(WebContents* source) {