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

content/public/browser/web_contents_delegate.cc

Index: content/public/browser/web_contents_delegate.cc
===================================================================
--- content/public/browser/web_contents_delegate.cc	(revision 154307)
+++ content/public/browser/web_contents_delegate.cc	(working copy)
@@ -25,6 +25,14 @@
   return NULL;
 }
 
+bool WebContentsDelegate::AddNewContents(WebContents* source,
+                                         WebContents* new_contents,
+                                         WindowOpenDisposition disposition,
+                                         const gfx::Rect& initial_pos,
+                                         bool user_gesture) {
+  return true;
+}
+
 bool WebContentsDelegate::IsPopupOrPanel(const WebContents* source) const {
   return false;
 }