Add a nice install paths for module SDKs and exports.

Following how NDK also creates its own install path.

Bug: 142935992
Test: cc_sdk_test.go, java_sdk_test.go
Change-Id: I98a3656903f37f6d7c90e6cf609431b2461a6161
diff --git a/android/paths.go b/android/paths.go
index c4b1073..8bb9a96 100644
--- a/android/paths.go
+++ b/android/paths.go
@@ -1276,8 +1276,8 @@
 	return ret
 }
 
-func PathForNdkInstall(ctx PathContext, paths ...string) InstallPath {
-	paths = append([]string{"ndk"}, paths...)
+func pathForNdkOrSdkInstall(ctx PathContext, prefix string, paths []string) InstallPath {
+	paths = append([]string{prefix}, paths...)
 	path, err := validatePath(paths...)
 	if err != nil {
 		reportPathError(ctx, err)
@@ -1285,6 +1285,14 @@
 	return InstallPath{basePath{path, ctx.Config(), ""}, ""}
 }
 
+func PathForNdkInstall(ctx PathContext, paths ...string) InstallPath {
+	return pathForNdkOrSdkInstall(ctx, "ndk", paths)
+}
+
+func PathForMainlineSdksInstall(ctx PathContext, paths ...string) InstallPath {
+	return pathForNdkOrSdkInstall(ctx, "mainline-sdks", paths)
+}
+
 func InstallPathToOnDevicePath(ctx PathContext, path InstallPath) string {
 	rel := Rel(ctx, PathForOutput(ctx, "target", "product", ctx.Config().DeviceName()).String(), path.String())