Changes the DEPS file to pull down the Dart VM source.

This pulls in the most recent dev-channel release of the
Dart source. It includes the Dart Editor, but it is planned
that this will be removed in the near future, which will
reduce checkout size.

The Dart source is under src/dart/dart. The disadvantage is
that this looks a bit silly, but it means that we don't have
to create/maintain yagr (Yet Another Git Repo).

From here, I'll work on translating the Dart gyp files over
to GN.

BUG=
R=jamesr@chromium.org

Review URL: https://codereview.chromium.org/670263008
diff --git a/DEPS b/DEPS
index 22b9e78..6eadb5b 100644
--- a/DEPS
+++ b/DEPS
@@ -54,7 +54,7 @@
 }
 
 # Only these hosts are allowed for dependencies in this DEPS file.
-# If you need to add a new host, contact chrome infrastracture team.
+# If you need to add a new host, contact chrome infrastructure team.
 allowed_hosts = [
   'chromium.googlesource.com',
   'boringssl.googlesource.com',