Chris Bracken

Added `tools/roll_dart` in 486b9c069d494eb19016c4079c37a1a9d5ff16b1 and 84627e370843b26a44a391858d0fcaba27502c47. This automates the process of generating the diff required to roll the Dart SDK version in repositories.bzl and README.md. Remaining work: * [ ]...

> the goal of Int64 should be to emulate the behavior of Dart's int in native (just adding web support), but it does not work that way. I switched roles...

`gen_snapshot_arm64` and `gen_snapshot_x64` for macOS are now migrated to universal binaries on `master` branch. iOS/Android gen_snapshots will be landing next.

`gen_snapshot_arm64` executables for iOS builds are migrated to universal binaries on `master` branch as of https://github.com/flutter/flutter/pull/152278. Android `gen_snapshot`s and `libimobiledevice` tooling will be landing next.

I expect I won't make any further progress on this until Q1 of 2025 given current priorities.

I'll need a followup patch that supports local engine development in the tool, but Android gen_snapshot is done for end users on `master` branch.

local engine cleanup will land in https://github.com/flutter/flutter/pull/164453.