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

chrome/browser/ui/views/external_tab_container_win.cc

Index: chrome/browser/ui/views/external_tab_container_win.cc
===================================================================
--- chrome/browser/ui/views/external_tab_container_win.cc	(revision 154307)
+++ chrome/browser/ui/views/external_tab_container_win.cc	(working copy)
@@ -461,7 +461,7 @@
   }
 }
 
-void ExternalTabContainerWin::AddNewContents(WebContents* source,
+bool ExternalTabContainerWin::AddNewContents(WebContents* source,
                                              WebContents* new_contents,
                                              WindowOpenDisposition disposition,
                                              const gfx::Rect& initial_pos,
@@ -470,7 +470,7 @@
     DCHECK(pending_);
     LOG(ERROR) << "Invalid automation provider. Dropping new contents notify";
     delete new_contents;
-    return;
+    return true;
   }
 
   scoped_refptr<ExternalTabContainerWin> new_container;
@@ -511,7 +511,7 @@
     Profile* profile = tab_contents->profile();
     tab_contents.release();  // Ownership has been transferred.
     if (route_all_top_level_navigations_) {
-      return;
+      return true;
     }
     uintptr_t cookie = reinterpret_cast<uintptr_t>(new_container.get());
     pending_tabs_.Get()[cookie] = new_container;
@@ -529,6 +529,7 @@
   } else {
     NOTREACHED();
   }
+  return true;
 }
 
 void ExternalTabContainerWin::WebContentsCreated(WebContents* source_contents,