On Dart core libraries we've introduced a library fork in experimental/lib_v2. Discussions and prototypes on Streams (called “Observable” in C#). Started work on refactoring the collections library. (Almost) removed library core_impl. noSuchMethod now takes an InvocationMirror.
In the dart:io library, we've implemented HTTP session and HTTP basic authentication support. We fixed bugs in the HTTP library and fixed a bug that caused Pub to fail (because of accessing files open in other processes on Windows). We're also working on improving IO performance and started landing HTTPS support.
For dart:html, we now have implementations and interfaces merged, dart:svg is split from dart:html and there's new support for keycodes.
In the Dart VM, the GC is now collecting unreferenced compiled code to avoid running out of code heap. The compiler now has bounds check elimination for some array accesses and we're doing investigations into better mega-morphic call site dispatch and landed first handling of related excessive de-optimizations. In the runtime, we've changed internal string representation to be UTF-16 in accordance to the updated language specification. Finally, we've worked on stability and bug fixes.
In the Dart Editor there's a new auto-recovery feature: The content of open editors is remembered and restored if a crash occurs. The Editor now uses the dart2js snapshot in the SDK. Compile times for the clock sample went from 9.8 seconds to 4.6 seconds. Saves in the editor are significantly faster. Times for our test file for saves went from 900ms to 30ms. The editor reports errors for using deprecated #library #import #source directives. It also resolves and refactor-renames [id] and [new id] references in documentation comments. Quick Fix to create missing “part” file.
On Pub, we've fixed bugs and improved error messages, created an HTTP package, added curl (for HTTPS) and multipart MIME support to HTTP package and uploaded lots of packages!
On Dart Web Components, we added ability to compose web components out of other components, the spec is in progress and we continued to fix many bugs from use community.