Revert "Constant fold charCodeAt via constant system"

TBR=johnniwinther@google.com
BUG=

Review URL: https://codereview.chromium.org//664283004

git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge@41382 260f80e4-7a28-3924-810f-c04153c831b5
Add SpanScanner.location.

Also explicitly expose FileSpans and FileLocations.

R=rnystrom@google.com

Review URL: https://codereview.chromium.org//683323002

git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge@41383 260f80e4-7a28-3924-810f-c04153c831b5
Redo "Constant fold charCodeAt via constant system"

TBR=johnniwinther@google.com
BUG=

Review URL: https://codereview.chromium.org//682243004

git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge@41384 260f80e4-7a28-3924-810f-c04153c831b5
Add patch for todomvc (temporary while we migrate to package bots logic)
R=ricow@google.com

Review URL: https://codereview.chromium.org//683063006

git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge@41385 260f80e4-7a28-3924-810f-c04153c831b5
Reverts 41378 for test failure.

Review URL: https://codereview.chromium.org//688443005

git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge@41386 260f80e4-7a28-3924-810f-c04153c831b5