Properly tolerate missing declaring source files

Broken in 228d6b8a4f0a21c1e9b2372c3104ce4ee19f65b4

(cherry picked from commit 7c6aca27dd2df58ac3d83a93ec5848e2b7d3159a)

Bug: 13575571
Bug: 12802375
Change-Id: Ia8a3196b15f8ed29810d0b6f09f81c7ae4e7480e
1 file changed