Adding guard to incremental force layout SetFixed

Without this extra guard, this was causing invalid memory
accesses when the incremental layout had not yet been initialized.

Change-Id: Ic3d00c2d5ba2d93bafb5b3afcc333c21e5d58a2e
Merge topic 'incremental-layout-guard' into master

8d300df4 Adding guard to incremental force layout SetFixed