- Implement a first cut for const String.env in the VM to allow

sdk/lib/core/bool.dart

Index: sdk/lib/core/bool.dart
===================================================================
--- sdk/lib/core/bool.dart	(revision 28841)
+++ sdk/lib/core/bool.dart	(working copy)
@@ -24,4 +24,12 @@
   String toString() {
     return this ? "true" : "false";
   }
+
+  /**
+   * Returns the boolean value of the given environment variable [name].
+   * The [defaultValue] is returned if [name] is not present in the environment
+   * or if its value is not a boolean.
+   */
+  external const factory bool.fromEnvironment(String name,
+                                             {bool defaultValue: false});
 }