Introduce background.scripts feature for extension manifests.

chrome/browser/extensions/extension_service_unittest.cc

Index: chrome/browser/extensions/extension_service_unittest.cc
diff --git a/chrome/browser/extensions/extension_service_unittest.cc b/chrome/browser/extensions/extension_service_unittest.cc
index 7494b0a925539be74015efaff5b4521bb1247348..801ca8bc79971737d89a57130969fcbb70a28720 100644
--- a/chrome/browser/extensions/extension_service_unittest.cc
+++ b/chrome/browser/extensions/extension_service_unittest.cc
@@ -1097,7 +1097,7 @@ TEST_F(ExtensionServiceTest, LoadAllExtensionsFromDirectorySuccess) {
   EXPECT_EQ(std::string("My extension 2"), loaded_[1]->name());
   EXPECT_EQ(std::string(""), loaded_[1]->description());
   EXPECT_EQ(loaded_[1]->GetResourceURL("background.html"),
-            loaded_[1]->background_url());
+            loaded_[1]->GetBackgroundURL());
   EXPECT_EQ(0u, loaded_[1]->content_scripts().size());
   // We don't parse the plugins section on Chrome OS.
 #if defined(OS_CHROMEOS)