Some clarifications in preparation to automatically order linker dependencies

Test: Browse the code and determine whether it's easier to understand
Bug: 66260943
Change-Id: I88c24a8a31ef68f428919087d206433659265684
diff --git a/cc/proto.go b/cc/proto.go
index a01951f..6e3cce7 100644
--- a/cc/proto.go
+++ b/cc/proto.go
@@ -60,14 +60,14 @@
 
 	switch proptools.String(p.Proto.Type) {
 	case "full":
-		if ctx.sdk() {
+		if ctx.useSdk() {
 			lib = "libprotobuf-cpp-full-ndk"
 			static = true
 		} else {
 			lib = "libprotobuf-cpp-full"
 		}
 	case "lite", "":
-		if ctx.sdk() {
+		if ctx.useSdk() {
 			lib = "libprotobuf-cpp-lite-ndk"
 			static = true
 		} else {