apex: choose stub according to min_sdk_version

Native modules within APEX should be linked with proper stub version
according to its min_sdk_version.

For example, when min_sdk_version is set to "29", libfoo in the apex
would be linked to libbar of version 29 from platform, even if it has
a newer version like 30.

Bug: 145796956
Test: m nothing (soong tests)
Change-Id: I4a0b2002587bc24b7deeb5d59b6eeba5e1db5b1f

apex/apex.go

@@ -19,6 +19,7 @@ import (
 	"path"
 	"path/filepath"
 	"sort"
+	"strconv"
 	"strings"
 	"sync"
 
@@ -1028,7 +1029,15 @@ func apexDepsMutator(mctx android.TopDownMutatorContext) {
 	var apexBundles []android.ApexInfo
 	var directDep bool
 	if a, ok := mctx.Module().(*apexBundle); ok && !a.vndkApex {
-		apexBundles = []android.ApexInfo{{mctx.ModuleName(), proptools.Bool(a.properties.Legacy_android10_support)}}
+		minSdkVersion := a.minSdkVersion(mctx)
+
+		apexBundles = []android.ApexInfo{
+			android.ApexInfo{
+				ApexName:               mctx.ModuleName(),
+				LegacyAndroid10Support: proptools.Bool(a.properties.Legacy_android10_support),
+				MinSdkVersion:          minSdkVersion,
+			},
+		}
 		directDep = true
 	} else if am, ok := mctx.Module().(android.ApexModule); ok {
 		apexBundles = am.ApexVariations()
@@ -1967,6 +1976,18 @@ func (a *apexBundle) walkPayloadDeps(ctx android.ModuleContext,
 	})
 }
 
+func (a *apexBundle) minSdkVersion(ctx android.BaseModuleContext) int {
+	ver := proptools.StringDefault(a.properties.Min_sdk_version, "current")
+	if ver != "current" {
+		minSdkVersion, err := strconv.Atoi(ver)
+		if err != nil {
+			ctx.PropertyErrorf("min_sdk_version", "should be \"current\" or <number>, but %q", ver)
+		}
+		return minSdkVersion
+	}
+	return android.FutureApiLevel
+}
+
 // Ensures that the dependencies are marked as available for this APEX
 func (a *apexBundle) checkApexAvailability(ctx android.ModuleContext) {
 	// Let's be practical. Availability for test, host, and the VNDK apex isn't important