Allow manifest handlers to declare keys they depend on that must be parsed before them.

chrome/common/extensions/manifest_tests/extension_manifests_override_unittest.cc

 // 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.
 
 #include "chrome/common/extensions/extension_manifest_constants.h"
 #include "chrome/common/extensions/manifest_handler.h"
 #include "chrome/common/extensions/manifest_tests/extension_manifest_test.h"
 #include "chrome/common/extensions/manifest_url_handler.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 namespace errors = extension_manifest_errors;
 
 class URLOverridesManifestTest : public ExtensionManifestTest {
   virtual void SetUp() OVERRIDE {
     ExtensionManifestTest::SetUp();
-    extensions::ManifestHandler::Register(keys::kChromeURLOverrides,
-                                          new extensions::URLOverridesHandler);
+    extensions::ManifestHandler::Register(
+        extension_manifest_keys::kChromeURLOverrides,
+        make_linked_ptr(new extensions::URLOverridesHandler));
   }
 };
 
 TEST_F(URLOverridesManifestTest, Override) {
   Testcase testcases[] = {
     Testcase("override_newtab_and_history.json", errors::kMultipleOverrides),
     Testcase("override_invalid_page.json", errors::kInvalidChromeURLOverrides)
   };
   RunTestcases(testcases, arraysize(testcases),
                EXPECT_TYPE_ERROR);
 
   scoped_refptr<extensions::Extension> extension;
 
   extension = LoadAndExpectSuccess("override_new_tab.json");
   EXPECT_EQ(extension->url().spec() + "newtab.html",
             extensions::URLOverrides::GetChromeURLOverrides(extension).
                 find("newtab")->second.spec());
 
   extension = LoadAndExpectSuccess("override_history.json");
   EXPECT_EQ(extension->url().spec() + "history.html",
             extensions::URLOverrides::GetChromeURLOverrides(extension).
                 find("history")->second.spec());
 }