Roll Dart to f445c318184b30b3db997ac27f357bcb5d45670a.

Fuchsia issue TO-365

Fixes https://github.com/flutter/flutter/issues/10061

See also https://github.com/flutter/engine/pull/3701

* Roll dart and buildroot deps since they have to be updated together to get and use prebuilt dart sdk in correct location.

* Update license

Fixes https://github.com/flutter/flutter/issues/11007

Fix target name for flutter_patched_sdk so it doesn't conflict with patched_sdk target name, doesn't confuse ninja with depfile defined as .d (#3834)

* Revert "Revert "Reland "Run Flutter on iOS and Android with color correct Skia" (#3818)" (#3823)"

This reverts commit db8d8a99.

* Fix test code to match internal API change

* Build Flutter patched-sdk with kernel artifacts

* Switch to new dart_host_toolchain argument mechanism to let dart patch_sdk know of host_toolchain.

* Update dart dependency

* Updated licenses

* Rename dart dependencies tag so they have just 'dart_'-prefixed dart's names.

* Fix indentation and line breaks for newly added deps.

* Add toolchain for windows host

* Update dart revision

* Licenses

* Update licenses

* Revert changes to licenses_third_party

* preserve Window callback zones

Run Window callbacks in the zone they are registered in. This is consistent with how other native API work, such as `scheduleMicrotask`, `Timer`, and `dart:io`. This also enables the developers to use the `Zone` API to capture and log unhandled Dart errors.

* refactor wrapping

* new line

* fewer if checks; group getters/setters/fields

* inline _invokeOnPointerDataPacket

Fixes https://github.com/flutter/flutter/issues/10569

* Roll Skia

* Update licenses

This reverts commit fc70e6eb1e02ab1e6764b45690e4639bfd104cc1.

This reverts commit 2650f529.

* Revert "Revert "Run Flutter on iOS and Android with color correct Skia (#3743)" (#3775)"

This reverts commit cfe70e07.

* Enable sRGB on IO thread, too

* Add 4444 as a fallback rendering mode

* Use bare ptr to SkColorSpace (not sk_sp) in PrerollContext

* increase Vulkan GrContext resource cache limits to match android

* [content handler] tune VulkanSurfaceProducer allocation and recycling heuristics

This will make it easier to change mtl into a shared library.

This attempts to make the Canvas API and some related features more
likely to throw a Dart exception than crash when exposed to bad input.

Depends on rolling tonic to
https://fuchsia-review.googlesource.com/c/35742/ which this patch does
not yet do, but I wanted to put it up for review to see if it was even
a reasonable approach.

This allows the shell to be built normally for a Fuchsia host.

Fixes https://github.com/flutter/flutter/issues/10855

If restartInput is called twice in quick succession, then the IME may output
warnings related to usage of the obsolete connection resulting from the first
call.

Fixes https://github.com/flutter/flutter/issues/10730

Fixes https://github.com/flutter/flutter/issues/10571

Currently in `ps` all apps running under the Flutter content handler
show up as `flutter_runner`. This makes them hard to identify. This
change names the process after the final path component URL of the
application that's launched, prefixed with "flutter:".

In theory we could run more than one Flutter application in a single
content handler process, but we don't right now. If we do this logic
would have to change.

* Revert "Fix licenses_lib golden file (#3798)"

This reverts commit d8ac43c3.

* Revert "Remove ParagraphConstriants (#3796)"

This reverts commit 8ccf767f.

* Revert "Reland "Initial integration of libtxt with Flutter alongside Blink." (#3793)"

This reverts commit 3c049219.

ASL was deprecated in iOS 10 and started causing SIGPIPE issues in iOS
10.3. Under the iOS 8 SDK, syslog() stopped working as of iOS 10.3
devices, with the result that ASL stdout/stderr forwarding was the only
means of logging. The engine now builds against the iOS 10 SDK, with
deployment target of iOS 8. Under this SDK, syslog() works correctly
across all supported OS versions.

NOTE: This is a temporary fix to get developers unblocked. While this
does fix the SIGPIPE issue and put iOS logging on par with the Android
solution, the intent is to move to a dedicated communication channel
with flutter_tools that isn't log-based.