[Web Payments] Add "pencil" edit button to lists.

ui/vector_icons/edit.icon

Index: ui/vector_icons/edit.icon
diff --git a/ui/vector_icons/edit.icon b/ui/vector_icons/edit.icon
new file mode 100644
index 0000000000000000000000000000000000000000..0cbb1f786afa1e4d3ab8a899f72c583227fc5881
--- /dev/null
+++ b/ui/vector_icons/edit.icon
@@ -0,0 +1,21 @@
+// 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.
+
+CANVAS_DIMENSIONS, 48,
+MOVE_TO, 6, 34.51f,
+LINE_TO, 6, 42.01f,
+LINE_TO, 13.5f, 42.01f,
+LINE_TO, 35.62f, 19.89f,
+LINE_TO, 28.12f, 12.39f,
+LINE_TO, 6, 34.51f,
+CLOSE,
+MOVE_TO, 41.42f, 14.09f,
+CUBIC_TO, 42.2f, 13.31f, 42.2f, 12.05f, 41.42f, 11.27f,
+LINE_TO, 36.74f, 6.59f,
+CUBIC_TO, 35.96f, 5.81f, 34.7f, 5.81f, 33.92f, 6.59f,
+LINE_TO, 30.26f, 10.25f,
+LINE_TO, 37.76f, 17.75f,
+LINE_TO, 41.42f, 14.09f,
+CLOSE,
+END