Merge "cc: Add docstring for IsVndk() and UseVndk()"

cc/cc.go

@@ -1205,6 +1205,8 @@ func (c *Module) Init() android.Module {
 	return c
 }
 
+// UseVndk() returns true if this module is built against VNDK.
+// This means the vendor and product variants of a module.
 func (c *Module) UseVndk() bool {
 	return c.Properties.VndkVersion != ""
 }
@@ -1298,6 +1300,9 @@ func (c *Module) IsVndkPrivate() bool {
 	return false
 }
 
+// IsVndk() returns true if this module has a vndk variant.
+// Note that IsVndk() returns true for all variants of vndk-enabled libraries. Not only vendor variant,
+// but also platform and product variants of vndk-enabled libraries return true for IsVndk().
 func (c *Module) IsVndk() bool {
 	if vndkdep := c.vndkdep; vndkdep != nil {
 		return vndkdep.isVndk()