tree 6582aaf158697ff5fe888541e92389f1bc6f6e57
parent d81496084b4b9c2b183f9551733a745dc7ec567f
author Colin Cross <ccross@android.com> 1432065781 -0700
committer Colin Cross <ccross@android.com> 1432065781 -0700

Use proptools.CloneEmptyProperties

CloneEmptyProperties is much faster than CloneProperties followed
by ZeroProperties.  Cuts >100ms off soong_build runtime, which will
become more important when we start calling soong_build a second
time to automatically generate documentation.

Change-Id: I45d948b36d9937a21b13dab068c3ce9a60b5a59b