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

chrome/browser/extensions/extension_host.cc

Index: chrome/browser/extensions/extension_host.cc
===================================================================
--- chrome/browser/extensions/extension_host.cc	(revision 154307)
+++ chrome/browser/extensions/extension_host.cc	(working copy)
@@ -591,7 +591,7 @@
   FileSelectHelper::RunFileChooser(tab, params);
 }
 
-void ExtensionHost::AddNewContents(WebContents* source,
+bool ExtensionHost::AddNewContents(WebContents* source,
                                    WebContents* new_contents,
                                    WindowOpenDisposition disposition,
                                    const gfx::Rect& initial_pos,
@@ -609,14 +609,16 @@
     if (associated_contents &&
         associated_contents->GetBrowserContext() ==
             new_contents->GetBrowserContext()) {
-      associated_contents->AddNewContents(
-          new_contents, disposition, initial_pos, user_gesture);
-      return;
+      WebContentsDelegate* delegate = associated_contents->GetDelegate();
+      return delegate && delegate->AddNewContents(
+          associated_contents, new_contents, disposition, initial_pos,
+          user_gesture);
     }
   }
 
   ExtensionTabUtil::CreateTab(new_contents, extension_id_, disposition,
                               initial_pos, user_gesture);
+  return true;
 }
 
 void ExtensionHost::RenderViewReady() {