Precompile dependencies' executables for use with "pub run".

sdk/lib/_internal/pub/lib/src/package_graph.dart

Index: sdk/lib/_internal/pub/lib/src/package_graph.dart
diff --git a/sdk/lib/_internal/pub/lib/src/package_graph.dart b/sdk/lib/_internal/pub/lib/src/package_graph.dart
index 14913787b95be9a5c9a70ad98a672c5762a03332..4470e51bc6ae1abde3ab918cfe87ebd080e38719 100644
--- a/sdk/lib/_internal/pub/lib/src/package_graph.dart
+++ b/sdk/lib/_internal/pub/lib/src/package_graph.dart
@@ -7,6 +7,7 @@ library pub.package_graph;
 import 'entrypoint.dart';
 import 'lock_file.dart';
 import 'package.dart';
+import 'utils.dart';
 
 /// A holistic view of the entire transitive dependency graph for an entrypoint.
 ///
@@ -24,5 +25,26 @@ class PackageGraph {
   /// All transitive dependencies of the entrypoint (including itself).
   final Map<String, Package> packages;
 
+  /// A map of transitive dependencies for each package.
+  Map<String, Set<Package>> _transitiveDependencies;
+
   PackageGraph(this.entrypoint, this.lockFile, this.packages);
+
+  /// Returns all transitive dependencies of [package].
+  ///
+  /// For the entrypoint this returns all packages in [packages], which includes
+  /// dev and override. For any other package, it ignores dev and override
+  /// dependencies.
+  Set<Package> transitiveDependencies(String package) {
+    if (package == entrypoint.root.name) return packages.values.toSet();
+
+    if (_transitiveDependencies == null) {
+      var closure = transitiveClosure(mapMap(packages,
+          value: (_, package) => package.dependencies.map((dep) => dep.name)));
+      _transitiveDependencies = mapMap(closure,
+          value: (_, names) => names.map((name) => packages[name]).toSet());
+    }
+
+    return _transitiveDependencies[package];
+  }
 }