Enforce newapi check only if min_sdk_version < compile_sdk_version

- NewApi check should be enforced only if min_sdk_version is less than
  the compile_sdk_version (the opposite direction should be a different
  build-time error)
- Change the datatype of *sdkVersion to android.ApiLevel (from string)
  to support version comparisons

Test: go build ./java
Test: no changes in ninja file
Bug: 228956345

Change-Id: Ic408857db7760d912ef4694d2ed72c0b7106eb04
diff --git a/java/base.go b/java/base.go
index b925350..a076718 100644
--- a/java/base.go
+++ b/java/base.go
@@ -1481,11 +1481,11 @@
 	}
 
 	if ctx.Device() {
-		lintSDKVersionString := func(sdkSpec android.SdkSpec) string {
+		lintSDKVersion := func(sdkSpec android.SdkSpec) android.ApiLevel {
 			if v := sdkSpec.ApiLevel; !v.IsPreview() {
-				return v.String()
+				return v
 			} else {
-				return ctx.Config().DefaultAppTargetSdk(ctx).String()
+				return ctx.Config().DefaultAppTargetSdk(ctx)
 			}
 		}
 
@@ -1494,9 +1494,9 @@
 		j.linter.srcJars = srcJars
 		j.linter.classpath = append(append(android.Paths(nil), flags.bootClasspath...), flags.classpath...)
 		j.linter.classes = j.implementationJarFile
-		j.linter.minSdkVersion = lintSDKVersionString(j.MinSdkVersion(ctx))
-		j.linter.targetSdkVersion = lintSDKVersionString(j.TargetSdkVersion(ctx))
-		j.linter.compileSdkVersion = lintSDKVersionString(j.SdkVersion(ctx))
+		j.linter.minSdkVersion = lintSDKVersion(j.MinSdkVersion(ctx))
+		j.linter.targetSdkVersion = lintSDKVersion(j.TargetSdkVersion(ctx))
+		j.linter.compileSdkVersion = lintSDKVersion(j.SdkVersion(ctx))
 		j.linter.compileSdkKind = j.SdkVersion(ctx).Kind
 		j.linter.javaLanguageLevel = flags.javaVersion.String()
 		j.linter.kotlinLanguageLevel = "1.3"