Add "environment" parameter to spawnUri for String.fromEnvironment support.

sdk/lib/core/bool.dart

Index: sdk/lib/core/bool.dart
diff --git a/sdk/lib/core/bool.dart b/sdk/lib/core/bool.dart
index 8150219d02a0105fd468df416c26bd283d5025b3..d1f31d760f68caad1467b29d32cf0541f543298f 100644
--- a/sdk/lib/core/bool.dart
+++ b/sdk/lib/core/bool.dart
@@ -21,11 +21,19 @@ class bool {
    * In all other cases, including when there is no declaration for `name`,
    * the result is the [defaultValue].
    *
+   * The result is the same as would be returned by:
+   *
+   *     (const String.fromEnvironment(name) == "true")
+   *         ? true
+   *         : (const String.fromEnvironment(name) == "false")
+   *             ? false
+   *             : defaultValue
+   *
    * Example:
    *
    *     const loggingFlag = const bool.fromEnvironment("logging");
    *
-   * If you want to use a different truth-string, you can use the
+   * If you want to use a different truth-string than `"true"`, you can use the

[floitsch, 2015/09/22 09:36:46]

no need to codify the "true".

[Lasse Reichstein Nielsen, 2015/09/22 10:28:09]

It's intended as code, so I prefer it codified.

    * [String.fromEnvironment] constructor directly:
    *
    *     const isLoggingOn = (const String.fromEnvironment("logging") == "on");