* Send an event at startup with the protocol version and pid

The pid will help with some of the issues of terminate the process when launched through a shell script and the version will allow clients to make decisions about supported features.

I've also bumped the protocol version number for two reasons:

1. This change
2. We didn't increase it when we added the previous emulator commands

https://github.com/flutter/flutter/issues/17956

* Add a `debugInstrumentAction()` method that will wrap an action
  in a stopwatch and print the time it took to run the action.
* Add a global `debugInstrumentationEnabled` that will control
  whether `debugInstrumentAction()` does anything (even in debug
  builds).
* Add some basic instrumentation to `registerServiceExtension()`
* Temporarily enable the `debugInstrumentationEnabled` flag in the
  Gallery to give us better visibility into what's happening in
  https://github.com/flutter/flutter/issues/17956

This reverts commit 0f557e72.

Enable --sync-async in Flutter.
Fixes #16801 

This reverts commit dac1baf4.

This is with dart roll.

This is one before dart roll.

When running with --local-engine, build single-architecture apps, rather
than what's declared in the Xcode project.

By default, Flutter creates Xcode projects that generate universal
binaries supporting both armv7 and arm64 processors. Since local engine builds
are all single-architecture, override the Xcode project's ARCHS setting
with the appropriate value for the specific engine.

NOTE: this assumes engine paths consistent with those used in the engine
repo: 32-bit iOS engine builds end in _arm, 64-bit builds do not.

* Fully rename to hot restart

Follow-up change to https://github.com/flutter/flutter/commit/f48dec570c899d8e222f5b3b7cbebd7d19fe6843

* Review feedback

It should be calling `tile.getDistanceToActualBaseline()` rather than
`tile.getDistanceToBaseline()`.  This is causing us to hit assertions
`getDistanceToBaseline()`

Fixes #17801.

* Fix #16464: Pass hit test when a big child is inside RenderFittedBox, RenderTransform, RenderFractionalTranslation, or RenderFollowerLayer

* Override `hitTestChildren`

* RenderTransform and RenderFollowerLayer shouldn't check if they are hit
themselves

* Test the hit test for translated child into translated box

* Add hit test for `FractionalTranslation`

* Don't check if RenderFractionalTranslation is hit themself

* Add hit test for FractionalTranslation

* Add test for FractionalTranslation

* abd74ed Add support for physical keyboards on Android (flutter/engine#5324)
* bb75825 Update buildroot to pull in msvc updates. (flutter/engine#5366)
* df7a02d Roll src/third_party/skia a0047bc..20027ce (19 commits) (flutter/engine#5365)
* 15bb9b8 Generate .packages for both flutter_kernel_transformers and frontend_server in the same way (flutter/engine#5362)
* 983f39c Don't enable LTO on Windows hosts as the toolchain does not read the value. (flutter/engine#5364)
* fb709e2 [fuchsia] Plumbing for sharing between AOT snapshots. (flutter/engine#5351)
* 416418f Roll src/third_party/skia 75bf216..a0047bc (5 commits) (flutter/engine#5363)
* b607382 Improve licenses script (flutter/engine#5355)
* c8050e8 Generate frontend server's .packages from Dart .packages file instead of using pub get. (flutter/engine#5360)
* 4d89213 Roll src/third_party/skia 84a4e5c..75bf216 (5 commits) (flutter/engine#5361)
* f24fdba Roll src/third_party/skia/ e9c81ee2e..84a4e5c00 (1 commit) (flutter/engine#5359)
* c622c68 Roll src/third_party/skia/ 8517631bf..e9c81ee2e (1 commit) (flutter/engine#5358)
* 93b3b26 Roll src/third_party/skia/ d416083ee..8517631bf (3 commits; 2 trivial rolls) (flutter/engine#5357)
* 9b51b89 Roll src/third_party/skia/ 13235d896..d416083ee (3 commits) (flutter/engine#5356)

They've been mostly green since https://github.com/flutter/flutter/pull/17812

This reverts commit 39d7f22a.

Allows one to use a different core snapshot without a custom engine build by just packaging a different one in the APK.