Merge this repo into dart-lang/native #930
Description
As discussed on #430, we'd like to merge this repo with dart-lang/native.
The process of merging a (non-mono) repo into dart-lang/native can be found here: dart-lang/tools#100.
One additional step to take care with here is that on the first roll of dart-lang/native into the Dart SDK this repo needs to be removed from the DEPS: https://github.com/dart-lang/sdk/blob/e2aa60ddf362967e17e06ec08871d634a32832c1/DEPS#L149