Observe adding external extensions via windows registry.

extensions/browser/external_install_info.cc

Index: extensions/browser/external_install_info.cc
diff --git a/extensions/browser/external_install_info.cc b/extensions/browser/external_install_info.cc
new file mode 100644
index 0000000000000000000000000000000000000000..e6da3fa8a2c38dc7ddd3702f16798a366713cbe8
--- /dev/null
+++ b/extensions/browser/external_install_info.cc
@@ -0,0 +1,49 @@
+// Copyright 2016 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 "extensions/browser/external_install_info.h"
+
+#include "base/version.h"
+#include "url/gurl.h"
+
+namespace extensions {
+
+ExternalInstallInfo::ExternalInstallInfo(const std::string& extension_id,
+                                         int creation_flags,
+                                         bool mark_acknowledged)
+    : extension_id(extension_id),
+      creation_flags(creation_flags),
+      mark_acknowledged(mark_acknowledged) {}
+
+ExternalInstallInfoFile::ExternalInstallInfoFile(
+    const std::string& extension_id,
+    scoped_ptr<base::Version> version,
+    const base::FilePath& path,
+    Manifest::Location crx_location,
+    int creation_flags,
+    bool mark_acknowledged,
+    bool install_immediately)
+    : ExternalInstallInfo(extension_id, creation_flags, mark_acknowledged),
+      version(std::move(version)),
+      path(path),
+      crx_location(crx_location),
+      install_immediately(install_immediately) {}
+
+ExternalInstallInfoFile::~ExternalInstallInfoFile() {}
+
+ExternalInstallInfoUpdateUrl::ExternalInstallInfoUpdateUrl(
+    const std::string& extension_id,
+    const std::string& install_parameter,
+    scoped_ptr<GURL> update_url,
+    Manifest::Location download_location,
+    int creation_flags,
+    bool mark_acknowledged)
+    : ExternalInstallInfo(extension_id, creation_flags, mark_acknowledged),
+      install_parameter(install_parameter),
+      update_url(std::move(update_url)),
+      download_location(download_location) {}
+
+ExternalInstallInfoUpdateUrl::~ExternalInstallInfoUpdateUrl() {}
+
+}  // namespace extensions