Fix exception throwing in connection with process starting.
Fix exception throwing in connection with process starting.

For the run constructor, verify the arguments before starting the
underlying process.

R=sgjesse@google.com
BUG=
TEST=

Review URL: https://chromiumcodereview.appspot.com//10202014

git-svn-id: c93d8a2297af3b929165606efe145742a534bc71@6995 260f80e4-7a28-3924-810f-c04153c831b5

dartino/dart-sdk,dartino/dart-sdk,dartino/dart-sdk,dartino/dart-sdk,dartino/dart-sdk,dart-archive/dart-sdk,dart-archive/dart-sdk,dart-lang/sdk,dart-archive/dart-sdk,dart-lang/sdk,dart-lang/sdk,dartino/dart-sdk,dart-lang/sdk,dart-archive/dart-sdk,dartino/dart-sdk,dart-archive/dart-sdk,dart-lang/sdk,dart-lang/sdk,dart-lang/sdk,dart-archive/dart-sdk,dartino/dart-sdk,dart-archive/dart-sdk,dart-archive/dart-sdk,dartino/dart-sdk,dart-lang/sdk,dart-archive/dart-sdk