Consolidate manifest handler registration.

chrome/common/extensions/manifest_tests/extension_manifests_devtools_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.h"
 #include "chrome/common/extensions/extension_manifest_constants.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"
 
 class DevToolsPageManifestTest : public ExtensionManifestTest {
-  virtual void SetUp() OVERRIDE {
-    ExtensionManifestTest::SetUp();
-    (new extensions::DevToolsPageHandler)->Register();
-  }
 };
 
 TEST_F(DevToolsPageManifestTest, DevToolsExtensions) {
   LoadAndExpectError("devtools_extension_url_invalid_type.json",
                      extension_manifest_errors::kInvalidDevToolsPage);
 
   scoped_refptr<extensions::Extension> extension;
   extension = LoadAndExpectSuccess("devtools_extension.json");
   EXPECT_EQ(extension->url().spec() + "devtools.html",
             extensions::ManifestURL::GetDevToolsPage(extension).spec());
   EXPECT_TRUE(extension->HasEffectiveAccessToAllHosts());
 }