The hermetic Xcode tooling in that repo is not yet easily usable for
Xcode 9. There are two main issues:

1. The tooling currently assumes that macOS host builds should use
   Xcode 8, whereas iOS builds should use Xcode 9. Flutter builds should
   use Xcode 9 in all cases.
2. The tooling currently includes a bail-out condition for iOS builds
   that exits non-zero immediately (Chrome hasn't yet migrated its iOS
   build to this tooling).

In the meantime, I've manually updated the bot infra with Xcode 9 and
we'll continue to use the current find_xcode.py tooling until Chrome's
new Mac/iOS tooling is ready.

* rename glyph_position_x to glyph_lines
* use round instead of roundf
* return a range start/end struct in Paragraph::GetWordBoundary

* Support for accessibility label and hint

* review comments

* Roll dart to pick up fix for diagnostic server

* Fix runUnaryGuarded, runBinaryGuarded calls

* Revert changes to runUnaryGuarded, runBinaryGuarded as they seem to be local-only, perhaps dependent on version of analyzer

* Update third_party license hash. No changes to licenses

https://github.com/flutter/flutter/issues/11992

* do not reset the justify offset after each run within a line
* track word start/end ranges relative to the start of the text instead of the line

* Revert "Pass option to reuse an existing runtime controller (#4253)"

This reverts commit 57f361dc.

* Revert "Document the Porter-Duff operators. (#4250)"

This reverts commit b15fa9c6.

* Revert "Move channel and codec related files to common (#4225)"

This reverts commit 674a3f58.

* Move channel and codec related files to common

This is in preparation for implementing channel and plugin support
for macOS desktop builds.

This ensures that accessibility hints are played properly.

Use sentence capitalization for non-obscuretext fields of TextInputType.text
and TextInputType.multiline on iOS and Android.

madvise returns zero on success

* systems/settings channel split

* merge textScaleFactor and alwaysUse24HourFormat into flutter/settings channel

* add debugOverrideAlwaysUse24HourFormat

* implement textScaleFactor on iOS

* address comments

* remove debugOverrideAlwaysUse24HourFormat

* clang-format

minikin::LineBreaker does not convert newline characters into line breaks
in its output.  Previously libtxt's version of LineBreaker container a patch
that added a large width offset for a newline in order to force wrapping to
the next line.  This works if the offset exceeds the paragraph's width
constraint.  But if the paragraph is laid out with infinite width, then the
text after the newline will continue on the current output line.

This change separates the paragraph's text into newline delimited blocks and
feeds each block separately to the minikin LineBreaker.

Also, libtxt was breaking the input styled text runs at newline boundaries.
This is no longer necessary.

The output_name property of a template is typically relative to the
root_build_dir rather than the target_gen_dir. This patch makes flutter_app
consistent with this pattern.

See: https://github.com/realm/jazzy/issues/791

This declaration makes it easier for Fuchsia to include Flutter in the system
image.

* 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.