add CanvasKit to CIPD; make it a DEPS dependency; add a manual roller script

This PR fixes the crash caused by pressing dead keys on Win32.

* Enable Dart compressed pointers for 64-bit mobile targets

* Fix.

* Address code review comments.

Web engine required more complex generator configurations which forced
us change the generator values from list to a dict.

Bug: https://github.com/flutter/flutter/issues/81855

Fix a bug in a calculation when selection is at a wordwrap

* Basic changes

* Fix build

* Revert some changes

* Fix tests (ATP)

* Win32Message and inject messagelist

* wm builders

* Format

* Correct

* LowerCaseAUnhandled

* ShiftLeftKeyA

* Ctrl-A

* Ctrl-1

* Digit1OnFrenchLayout

* AltGrKeyQ

* Dead key E

* ^1

* Multibyte

* Format

* License

* Revert key.dart

* Move CreateKeyEventLparam

* MockEmbedderApiForKeyboard

* More MockEmbedderApiForKeyboard

* Doc

* Move MockMessageQueue

* is_deadchar doesnt seem needed

* ConvertChar32ToUtf8

* PeekNextMessageType

* Format

* Apply suggestions from code review
Co-authored-by: NGreg Spencer <gspencergoog@users.noreply.github.com>
Co-authored-by: NGreg Spencer <gspencergoog@users.noreply.github.com>

Enhances ui.KeyData.toString by:
- Fixing the character interpretation;
- Adding hex representation to characters;
- Applying the code to the web engine which is currently missing.