Make FrameLayout support mixed wrap_content/match_parent children.

Bug #3259668

If a FrameLayout is measured with an UNSPECIFIED or AT_MOST spec,
it cannot correctly define the size of its children set to
match_parent. This change adds a second measurement pass similar
to what LinearLayout does in the same situation.

Change-Id: I20ac5203c2efc2e559f88b2c9573d4ad7df488b4