Most of the framework widgets should work in terms of EdgeInsetsGeometry
rather than EdgeInsets so that their clients can supply directional
insets.

* enable lint prefer_final_fields

* enable lint recursive_getters

* enable lint unnecessary_overrides

Fixes #5215

Fixes #11381

This reverts commit ec25f6bd.

* Fixed TrackingScrollController cleaning stored offset on position's detach

* Fixed format.

* Fixed format.

extract_messages script currently fails to parse this file because of its use of static asserts, super and a ctr body. Since we already have an assert in the body, I think it is also more readable to put all of them together. _LocalizationScope follows the same pattern above.

This patch migrates iOS device listing from using Xcode instruments to
using the libimobiledevice tools idevice_id and ideviceinfo.

ideviceinfo was previously incompatible with iOS 11 physical devices;
this has now been fixed.

In 37bb5f13 flutter_tools migrated from
libimobiledevice-based device listing on iOS to using Xcode instruments
to work around the lack of support for iOS 11. Using instruments entails
several downsides, including a significantly higher performance hit, and
leaking hung DTServiceHub processes in certain cases when a simulator is
running, necessitating workarounds in which we watched for, and cleaned
up leaked DTServiceHub processes. This patch returns reverts the move to
instruments now that it's no longer necessary.

* rename Element.visitChildrenForSemantics to debugVisitOnstageChildren

* address comments

* Improve the Flex overflow marker style

* Update basic.dart

* Update Hot Reload label text in template app instructions.

* label fix

This adds --preview-dart-2 flag that enables use of Dart 2.0 Frontend in Flutter tools.

* Revert "Revert "fire service protocol events for frames (#11565)" (#11727)"

This reverts commit f25e2f52.

* move the postEvent() call into a separate method

Fixes #11373

This patch includes:

 * SliverPadding
 * ScrollView
 * PageView

Fixes #11764
Fixes #11836

* fix typo in State.didUpdateWidget

* rephrase

* upgrade to linter-0.1.35

* re-enable lint prefer_const_constructors

* address review comments

Fixes #11374

When scrolling vertically, the scrollbar is on the left in RTL.

* ensureVisible works with viewports that have a center child

* review feedback

Fixes #11369

Fixes #11358

Fixes #11389