* move the material_gallery/demos.dart script

* rename all_demos.dart to all.dart

Current numbers from my Nexus 5:
  "average_frame_build_time_millis": 22.6854,
  "missed_frame_build_budget_count": 15,
  "frame_count": 15

Filed https://github.com/flutter/flutter/issues/3296

@yjbanov @hansmuller @vlidholt

Fixes https://github.com/flutter/flutter/issues/2713

[driver] utility for extracting and saving timeline summary

* sort imports

And fix the zillion issues that uncovered.

This reverts commit f41b3411, reversing
changes made to e33d8d96.

This was a bad check-in due to my mangling uploading a new version of the branch from a different machine.

This reverts https://github.com/flutter/flutter/pull/2639 and will be replaced by https://github.com/flutter/flutter/pull/2640

And fix the zillion issues that uncovered.

And fix a zillion omissions this uncovered.