It's far from perfect, but the following use-case works:

- open an empty document with a singe slide (only two placeholder
  shapes)
- type a few characters (into the title shape), Esc to finish editing
- click into the non-title placeholder
- type + Esc -> characters appear in the non-title shape

Change-Id: Idc97c1fbeda0fb3ac53769e78b7cd665d8aee67b