Move background_page extension manifest key to background.page.

Move background_page to background.page so that additional
properties can be added to the background group in the future.

Only support background_page in older manifest versions.

BUG=107791

Review URL: http://codereview.chromium.org/9072015

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@116289 0039d316-1c4b-4281-b951-d872f2087c98
diff --git a/chrome/browser/extensions/component_loader_unittest.cc b/chrome/browser/extensions/component_loader_unittest.cc
index 2344564..bf5bb49 100644
--- a/chrome/browser/extensions/component_loader_unittest.cc
+++ b/chrome/browser/extensions/component_loader_unittest.cc
@@ -1,4 +1,4 @@
-// Copyright (c) 2011 The Chromium Authors. All rights reserved.
+// Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
@@ -161,7 +161,7 @@
 
   std::string string_value;
   manifest.reset(component_loader_.ParseManifest(manifest_contents_));
-  ASSERT_TRUE(manifest->GetString("background_page", &string_value));
+  ASSERT_TRUE(manifest->GetString("background.page", &string_value));
   ASSERT_EQ("backgroundpage.html", string_value);
 }