Make it so that allow_js_access: false can be used with background pages created by window.open.

chrome/common/extensions/extension.cc

Index: chrome/common/extensions/extension.cc
diff --git a/chrome/common/extensions/extension.cc b/chrome/common/extensions/extension.cc
index 4ef186a58bf4c447068aa6f00017e923e2699dd8..f6383c2134a3d1f88ed34f4e13591dcd0d63c902 100644
--- a/chrome/common/extensions/extension.cc
+++ b/chrome/common/extensions/extension.cc
@@ -1834,11 +1834,6 @@ bool Extension::LoadBackgroundAllowJSAccess(
     return false;
   }
 
-  if (!has_background_page()) {
-    *error = ASCIIToUTF16(errors::kInvalidBackgroundAllowJsAccessNoPage);
-    return false;
-  }
-
   return true;
 }