PaymentHandler: Implement GetAllPaymentApps().

content/public/browser/installed_payment_instrument.cc

Index: content/public/browser/installed_payment_instrument.cc
diff --git a/content/public/browser/installed_payment_instrument.cc b/content/public/browser/installed_payment_instrument.cc
new file mode 100644
index 0000000000000000000000000000000000000000..b3e8ddcb4bab6e9508548176f619ff23637388f2
--- /dev/null
+++ b/content/public/browser/installed_payment_instrument.cc
@@ -0,0 +1,13 @@
+// Copyright 2017 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 "content/public/browser/installed_payment_instrument.h"
+
+namespace content {
+
+InstalledPaymentInstrument::InstalledPaymentInstrument() = default;
+
+InstalledPaymentInstrument::~InstalledPaymentInstrument() = default;
+
+}  // namespace content