Make sure the google wallet in-app payment support app is always installed.

chrome/browser/extensions/external_component_loader.h

+// Copyright (c) 2013 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.
+
+#ifndef CHROME_BROWSER_EXTENSIONS_EXTERNAL_COMPONENT_LOADER_H_
+#define CHROME_BROWSER_EXTENSIONS_EXTERNAL_COMPONENT_LOADER_H_
+
+#include <string>
+
+#include "base/compiler_specific.h"
+#include "chrome/browser/extensions/external_loader.h"
+
+namespace extensions {
+
+// A specialization of the ExternalLoader that loads a hard-coded list of
+// external extensions, that should be considered components of chrome (but
+// unlike Component extensions, these extensions are installed from the webstore
+// and don't get access to component only APIs.
+// Instances of this class are expected to be created and destroyed on the UI
+// thread and they are expecting public method calls from the UI thread.
+class ExternalComponentLoader : public ExternalLoader {
+ public:
+  ExternalComponentLoader();
+
+ protected:
+  virtual void StartLoading() OVERRIDE;
+
+ private:
+  friend class base::RefCountedThreadSafe<ExternalLoader>;
+  virtual ~ExternalComponentLoader();
+
+  DISALLOW_COPY_AND_ASSIGN(ExternalComponentLoader);
+};
+
+}  // namespace extensions
+
+#endif  // CHROME_BROWSER_EXTENSIONS_EXTERNAL_COMPONENT_LOADER_H_