This implements const constructor fromEnvironment on bool, int and
String.
The VM have the added -Dname=value option to define the value for the
properties. All values are provided by using the -D - nothing is read
from the environment.
If the resulting value is null or - in the case of int.fromEnvironment
- not a number an ArgumentError is thrown.
This CL does not have any implementation for dart2js.
This is a continuation of the change
https://chromiumcodereview.appspot.com/24975002 by iposva@
BUG=
R=iposva@google.com
Review URL: https://codereview.chromium.org//50983002
git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge/dart@29642 260f80e4-7a28-3924-810f-c04153c831b5