Replace ApiStrToNum uses with ApiLevel.

Test: treehugger
Bug: http://b/154667674
Change-Id: I2954bb21c1cfdeb305f25cfb6c8711c930f6ed50
diff --git a/java/app.go b/java/app.go
index ae7373f..99943f2 100755
--- a/java/app.go
+++ b/java/app.go
@@ -436,7 +436,7 @@
 
 		if minSdkVersion, err := a.minSdkVersion().effectiveVersion(ctx); err == nil {
 			a.checkJniLibsSdkVersion(ctx, minSdkVersion)
-			android.CheckMinSdkVersion(a, ctx, int(minSdkVersion))
+			android.CheckMinSdkVersion(a, ctx, minSdkVersion.ApiLevel(ctx))
 		} else {
 			ctx.PropertyErrorf("min_sdk_version", "%s", err.Error())
 		}
@@ -1637,7 +1637,8 @@
 	return sdkSpecFrom("")
 }
 
-func (j *AndroidAppImport) ShouldSupportSdkVersion(ctx android.BaseModuleContext, sdkVersion int) error {
+func (j *AndroidAppImport) ShouldSupportSdkVersion(ctx android.BaseModuleContext,
+	sdkVersion android.ApiLevel) error {
 	// Do not check for prebuilts against the min_sdk_version of enclosing APEX
 	return nil
 }