This change exposes the view safe area insets (introduced in iOS 11) to
the framework via MediaQuery.of(context).padding. Safe area insets are
the view insets (padding) inside of which content can be relied on to
display without truncation/clipping, as would occur with e.g. the iPhone
X sensor notch.

As this API was added in iOS 11, we place it behind a runtime guard
checking OS level.

Until the runtime support for @avialable lands in the next Fuchsia
buildtools rev, ignore -Wunguarded-availability-new around the safe area
insets check and use an FML runtime check instead.

Refactor querying of supported Vulkan extensions.

* Android SeekBars announce their value

* style

Previously, these binaries were in /system/apps, which is going away. Also,
rename flutter_runner to flutter_jit_runner to match flutter_aot_runner.

Instead, the rasterizer can be accessed via the platform view.

* Fix regression - configure asset bundle

* Fix formatting

This will replace the one in the diagnostic server

* Only post UIAccessibilityLayoutChangedNotification if layout actually changed

* ++

* review comment

This reverts commit a48b5f6d.

Refactoring related to use of the embedder APIs on macOS
host builds.

* Read core platform kernel file during Dart initialization.

Currently service isolate is initialized from the source code parsed by VM.
This CL changes it so service isolate created during Dart initialization
is created from the kernel platform.dill file if it is present in the application
bundle. Then this platform kernel file is kept in dart_init module and reused
for application sciprt isolates.

* Reformat and merge

* Use accessor method

* Avoid passing running_from_kernel param. Add TODO for cleanup. Rename param.

* add luminance getter to color

* tests

* nit

This reverts the previous roll to 33397f which included an assertion we ended up tripping over on certain scenes. A Skia issue has been filed for this https://bugs.chromium.org/p/skia/issues/detail?id=7225.

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