Add product_variables.native_coverage.src

Test: m checkbuild
Fixes: 148088129
Change-Id: I38fb22b28de1176ed880708733f7e7f76bee2e50
diff --git a/android/variable.go b/android/variable.go
index de6621b..58e5940 100644
--- a/android/variable.go
+++ b/android/variable.go
@@ -127,6 +127,7 @@
 		} `android:"arch_variant"`
 
 		Native_coverage struct {
+			Src          *string  `android:"arch_variant"`
 			Srcs         []string `android:"arch_variant"`
 			Exclude_srcs []string `android:"arch_variant"`
 		} `android:"arch_variant"`