Run ErrorProne in OpenJDK9

Use the OpenJDK9 javac to run ErrorProne by adding it to
-processorpath and using -Xplugin:ErrorProne.

Bug: 69485063
Test: m RUN_ERROR_PRONE=true javac-check
Change-Id: I0496006b71b70766ef16d57753cbcf037897799c
diff --git a/java/builder.go b/java/builder.go
index 2a2ed23..1944e69 100644
--- a/java/builder.go
+++ b/java/builder.go
@@ -26,7 +26,6 @@
 	"github.com/google/blueprint"
 
 	"android/soong/android"
-	"android/soong/java/config"
 )
 
 var (
@@ -80,29 +79,6 @@
 		},
 		"kotlincFlags", "classpath", "srcJars", "srcJarDir", "outDir", "kotlinJvmTarget")
 
-	errorprone = pctx.AndroidStaticRule("errorprone",
-		blueprint.RuleParams{
-			Command: `rm -rf "$outDir" "$annoDir" "$srcJarDir" && mkdir -p "$outDir" "$annoDir" "$srcJarDir" && ` +
-				`${config.ZipSyncCmd} -d $srcJarDir -l $srcJarDir/list -f "*.java" $srcJars && ` +
-				`${config.SoongJavacWrapper} ${config.ErrorProneCmd} ` +
-				`$processorpath $javacFlags $bootClasspath $classpath ` +
-				`-source $javaVersion -target $javaVersion ` +
-				`-d $outDir -s $annoDir @$out.rsp @$srcJarDir/list && ` +
-				`${config.SoongZipCmd} -jar -o $out -C $outDir -D $outDir`,
-			CommandDeps: []string{
-				"${config.JavaCmd}",
-				"${config.ErrorProneJavacJar}",
-				"${config.ErrorProneJar}",
-				"${config.SoongZipCmd}",
-				"${config.ZipSyncCmd}",
-			},
-			CommandOrderOnly: []string{"${config.SoongJavacWrapper}"},
-			Rspfile:          "$out.rsp",
-			RspfileContent:   "$in",
-		},
-		"javacFlags", "bootClasspath", "classpath", "processorpath", "srcJars", "srcJarDir",
-		"outDir", "annoDir", "javaVersion")
-
 	turbine = pctx.AndroidStaticRule("turbine",
 		blueprint.RuleParams{
 			Command: `rm -rf "$outDir" && mkdir -p "$outDir" && ` +
@@ -161,6 +137,7 @@
 	javaVersion   string
 
 	errorProneExtraJavacFlags string
+	errorProneProcessorPath   classpath
 
 	kotlincFlags     string
 	kotlincClasspath classpath
@@ -208,26 +185,24 @@
 		desc += strconv.Itoa(shardIdx)
 	}
 
-	transformJavaToClasses(ctx, outputFile, shardIdx, srcFiles, srcJars, flags, deps, "javac", desc, javac)
+	transformJavaToClasses(ctx, outputFile, shardIdx, srcFiles, srcJars, flags, deps, "javac", desc)
 }
 
 func RunErrorProne(ctx android.ModuleContext, outputFile android.WritablePath,
 	srcFiles, srcJars android.Paths, flags javaBuilderFlags) {
 
-	if config.ErrorProneJar == "" {
-		ctx.ModuleErrorf("cannot build with Error Prone, missing external/error_prone?")
-	}
+	flags.processorPath = append(flags.errorProneProcessorPath, flags.processorPath...)
 
 	if len(flags.errorProneExtraJavacFlags) > 0 {
 		if len(flags.javacFlags) > 0 {
-			flags.javacFlags = flags.errorProneExtraJavacFlags + " " + flags.javacFlags
+			flags.javacFlags += " " + flags.errorProneExtraJavacFlags
 		} else {
 			flags.javacFlags = flags.errorProneExtraJavacFlags
 		}
 	}
 
 	transformJavaToClasses(ctx, outputFile, -1, srcFiles, srcJars, flags, nil,
-		"errorprone", "errorprone", errorprone)
+		"errorprone", "errorprone")
 }
 
 func TransformJavaToHeaderClasses(ctx android.ModuleContext, outputFile android.WritablePath,
@@ -276,7 +251,7 @@
 func transformJavaToClasses(ctx android.ModuleContext, outputFile android.WritablePath,
 	shardIdx int, srcFiles, srcJars android.Paths,
 	flags javaBuilderFlags, deps android.Paths,
-	intermediatesDir, desc string, rule blueprint.Rule) {
+	intermediatesDir, desc string) {
 
 	deps = append(deps, srcJars...)
 
@@ -308,7 +283,7 @@
 		annoDir = filepath.Join(shardDir, annoDir)
 	}
 	ctx.Build(pctx, android.BuildParams{
-		Rule:        rule,
+		Rule:        javac,
 		Description: desc,
 		Output:      outputFile,
 		Inputs:      srcFiles,