Add sample directories to the package config.

This allows the package imports in the tests to resolve.

Change-Id: Idadca8b55516a5b5d1511ebc38c298479aa8eda0
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/333662
Commit-Queue: Nate Bosch <nbosch@google.com>
Auto-Submit: Jake Macdonald <jakemac@google.com>
Reviewed-by: Nate Bosch <nbosch@google.com>

samples/ffi/http/pubspec.yaml

@@ -1,4 +1,4 @@
-name: http
+name: http_sample
 version: 0.0.1
 publish_to: none
 

samples/ffi/http/test/http_test.dart

@@ -6,7 +6,7 @@ import 'dart:async';
 
 import 'package:test/test.dart';
 
-import 'package:http/http.dart';
+import 'package:http_sample/http.dart';
 
 Future<void> main() async {
   test('httpGet', () async {

tools/generate_package_config.dart

@@ -57,13 +57,16 @@ void main(List<String> args) {
     platform('pkg/vm/testcases'),
   ];
 
+  var sampleDirs = listSubdirectories(platform('samples')).toList();
+
   // Validate that all the given directories exist.
   var hasMissingDirectories = false;
   for (var path in [
     ...packageDirs,
     ...cfePackageDirs,
     ...feAnalyzerSharedPackageDirs,
-    ...pkgVmPackageDirs
+    ...pkgVmPackageDirs,
+    ...sampleDirs,
   ]) {
     if (!Directory(join(repoRoot, path)).existsSync()) {
       stderr.writeln("Unable to locate directory: '$path'.");
@@ -81,6 +84,7 @@ void main(List<String> args) {
     ...makeFeAnalyzerSharedPackageConfigs(feAnalyzerSharedPackageDirs),
     ...makeFrontendServerPackageConfigs(frontendServerPackageDirs),
     ...makePkgVmPackageConfigs(pkgVmPackageDirs),
+    ...makePackageConfigs(sampleDirs),
   ];
   packages.sort((a, b) => a.name.compareTo(b.name));