* Fix for issue 12526

Ensure that child isolates do not clear the dart_ui_state_ field present in the dart controller.

The commit https://github.com/flutter/engine/commit/dd1e0b59ece026737b05640cf020a6e590cfc10c implemented code to reset the dart_ui_state_ back to null when an isolate was being shutdown to ensure there was no use after free issues when the main isolate exeutes Isolate.current.kill() it however it was also clearning the field when a child isolate was shutdown causing SEGVs later.

* Address code format issues.

Just log them as errors

* Add dependency on chromium/src/build for Mac/iOS build

Preparation for migrating to mac_toolchain.py for installing/configuring
Xcode versions on the Mac build bots.

* Exclude third_party/chromium_build from licence script

It's used only at build time to fetch and install the correct Xcode
version.

maxIntrinsicWidth is the sum of the width of all lines in the input
(if the width were any smaller, the renderer might have to wrap a line)

minIntrinsicWidth is the maximum width of a word (if the paragraph were
any narrower, the renderer would have to truncate a word)

It was accidently removed in a5e26f1f.

This is for Fuchsia where we would like it to be located at //third_party/flutter.

This registers a test font manager that maps all fonts to the Ahem font

Fixes https://github.com/flutter/flutter/issues/12513

They help the analysis service identify packages and are now mandatory on Fuchsia.

ClearDartWrapper will delete this SceneBuilder, causing deletion of the
LayerBuilder

This was used by AndroidSurfaceSoftware but is now obsolete

Make sure we await for the file writing to complete before reporting that compilation is done. (#4210)

* Fix RunBundleAndSource to run from kernel.

This is needed to accommodate restarting(rather than reload) of Flutter app from kernel.

* Fix formatting

Move layer tree construction into flow::LayerBuilder so alternate builders can be plugged in. (#4197)

* Roll dart to 87538ffd7eca3405d13e46dcf3a20dcdcde9761e

* Update license hash

* Revert "Revert "Change kernel platform generation dependency name (#4189)" (#4192)"

This reverts commit a91e7b0c.

* Remove bad change that broke the build

* Remove comma

This reverts commit fa46eca4.

This reverts commit 83224fb6.

* Change kernel platform generation dependency name

* Include vmservice which is needed by gen_snapshot for Flutter release build

...if the environment is already setup

* Add reset method to reset incremental compiler.

This is needed to support Flutter app restart request.

* Indent constructor calls