Add CPS IR transformation to make the JavaScript backend specific semantics explicit in the tree.

Also implement transformation to insert boolean conversion.

R=kmillikin@google.com

Review URL: https://codereview.chromium.org//735253003

git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge@41979 260f80e4-7a28-3924-810f-c04153c831b5
Handle IPv6 addresses for HTTP client requests

The Host header was not set correctly for HTTP requests when an IPv6 address
was used. The square brackets surrounding the address was missing.

BUG=http://dartbug.com/21698
R=lrn@google.com

Review URL: https://codereview.chromium.org//755883007

git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge@41980 260f80e4-7a28-3924-810f-c04153c831b5