override chrome:// URLs via extensions.

chrome/browser/extensions/extension_override_apitest.cc

Index: chrome/browser/extensions/extension_override_apitest.cc
diff --git a/chrome/browser/extensions/extension_override_apitest.cc b/chrome/browser/extensions/extension_override_apitest.cc
new file mode 100644
index 0000000000000000000000000000000000000000..9ab0b1f1999379ad245cd4f742016160f549ce59
--- /dev/null
+++ b/chrome/browser/extensions/extension_override_apitest.cc
@@ -0,0 +1,13 @@
+// Copyright (c) 2009 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/browser/extensions/extension_apitest.h"
+
+IN_PROC_BROWSER_TEST_F(ExtensionApiTest, Overrides) {
+  ASSERT_TRUE(RunExtensionTest("override1")) << message_;  // new tab
+  EXPECT_EQ(results_.size(), 0);
+
+  // TODO(erikkay) load a second override and verify behavior, then unload
+  // the first and verify behavior, etc.
+}