Stop running pub get at gclient sync time and fix build bugs

mojo/public/dart/third_party/http_multi_server/CHANGELOG.md

+## 1.3.2
+
+* Eventually stop retrying port allocation if it fails repeatedly.
+
+* Properly detect socket errors caused by already-in-use addresses.
+
+## 1.3.1
+
+* `loopback()` and `loopbackSecure()` recover gracefully if an ephemeral port is
+  requested and the located port isn't available on both IPv4 and IPv6.
+
+## 1.3.0
+
+* Add support for `HttpServer.autoCompress`.
+
+## 1.2.0
+
+* Add support for `HttpServer.defaultResponseHeaders.clear`.
+
+* Fix `HttpServer.defaultResponseHeaders.remove` and `.removeAll`.
+
+## 1.1.0
+
+* Add support for `HttpServer.defaultResponseHeaders`.
+
+## 1.0.2
+
+* Remove the workaround for [issue 19815][].
+
+## 1.0.1
+
+* Ignore errors from one of the servers if others are still bound. In
+  particular, this works around [issue 19815][] on some Windows machines where
+  IPv6 failure isn't discovered until we try to connect to the socket.
+
+[issue 19815]: http://code.google.com/p/dart/issues/detail?id=19815