* PopupMenuButton: create IconButton if child is Icon

Otherwise the resulting button has an abnormally small and rectangular
area. With multiple PopupMenuButton(child: Icon) they get squished
together in the AppBar.

* Add separate icon argument to PopupMenuButton

* Fix style issues and tweak dartdocs

* Add tests for icon argument to PopupMenuButton

* Group icon tests and fix broken test, analyzer warnings

* Test that the correct custom icon is present

* Apply De Morgan's to work around dart analyzer bug

see: https://github.com/dart-lang/sdk/issues/30288

* Revert "Make plugins add their repos to projects in the consuming app (#11447)"

This reverts commit abe1e252.

* Revert "Support for custom build types on Android (#11354)"

This reverts commit 87eec719.

* Revert "add a profile() method (#11443)"

This reverts commit 561d17a8.

* Revert "Fix documentation based on dartdoc's warnings (#11428)"

This reverts commit 6655074b.

* Revert "Improve some docs around WillPopScope. (#11429)"

This reverts commit 58a28a29.

* Revert "temporarily disable broken driver test in integration_ui (#11440)"

This reverts commit 764515ec.

* Revert "style fix"

This reverts commit 00bfc866.

* Revert "tests for waitFor/waitForAbsent"

This reverts commit 31d2ee9c.

* Revert "Always evaluate the finder in `driver.waitFor()` and `driver.waitForAbsent()`"

This reverts commit 11d7c79b.

* roll

* no-op commit

* revert no-op

It has recently come to light that we may have been ordering saveLayer
calls and clip calls incorrectly.

* add a profile() method

* add todos

...and break the navigator<->routes circular dependency.

This is a step towards fixing https://github.com/flutter/flutter/issues/9577 but doesn't yet do so.

Fixes #11327

This reverts commit 4b4cabb7.

* fire service protocol extension events for frames

* start time in micros

* introduce a profile() function; only send frame events when in profile (or debug) modes

* moved the profile() function to foundation/profile.dart

* refactor to make the change more testable; test the change

* fire service protocol events by listening to onFrameInfo

* remove the frame event stream; add a devicelab test

* remove a todo

* final

The output location of gen_snapshot differs based on the engine's target
platform, and we don't know the target platform when building a
platform-independent FLX in JIT mode.

It was 8.0. It's now arbitrarily 18.0.

Changing this required adjusting some tests. Adjusting the tests
required debugging the tests. Debugging the tests required some tools
to help debugging gesture recognizers and gesture arenas, so I added
some. It also required updating some toString() methods which resulted
in some changes to the tree diagnostics logic.

Also I cleaned up some docs while I was at it.

* remove the flutter view cache; fix the ability to quit the app after a full restart

* improve test

* update test

Refactor RenderObject.toStringDeep and Widget.toStringDeep code to use DiagnosticsNode.

This reverts commit bc4a3f17.

* Support automaticallyImplyLeading param in AppBar

* Review fixes

* fix review comments

* ignore postpauseevents when reloading

* Update run_hot.dart

comment changes to kick the appveyor bot

Fixes https://github.com/flutter/flutter/issues/11323

Mainly, this adds documentation to members that were previously
lacking documentation.

It also adds a big block of documentation about improving performance
of widgets.

This also removes some references to package:collection and adds
global setEquals and listEquals methods in foundation that we can use.
(setEquals in particular should be much faster than the
package:collection equivalent, though both should be faster as they
avoid allocating new objects.) All remaining references now qualify
the import so we know what our remaining dependencies are.

Also lots of code reordering in Flutter driver to make the code
consistent and apply the style guide more thoroughly.

* Fix physics with NestedScrollView

* Review feedback

* Optimise AnimatedSize for the tight case.
* Remove `default` from a switch statement over enum (so that analyzer will complain if we add enum values).
* Adopt the Size since we use it after the child may have changed (which would throw normally).
* AnimatedCrossFade.layoutBuilder

* Flutter create widget test template.

Running `flutter create —with-widget-test` produces a test/widget_test.dart sample widget test.

* Generate widget test bits in flutter create.

* Path fix.

* Added types.

* Skip shell testing on windows.

* formatting fixes

* Update test sample to test the sample app.

* Formatting tweak.

* Prefix and Suffix support for TextFields

* Adding Tests

* Removing spurious newline.

* Fixing a small problem with the test

* Code review changes

* Code Review Changes

* Review Changes

* Export the new StrokeJoin enum

* Added example for line styles, and enabled line join styles.

* Reverting inadvertent change to main.dart.

* Updated due to code review of engine code

* Removed example.

* Added arguments to named routes, with test.

* Fixing some formatting

* Fixing Navigator.pop for named routes.

* Fixing comment.

* Simplifying test.

* Fixing new -> const for Text object.

* Tiny text change (also to kick a new Travis build)

* Added a more realistic test case.

* Reverting unintentional iml changes.

* Fixing trailing newline

* Removing some changes that snuck in.

Extract common text selection overlay logic from Material to Widget and create a Cupertino version of the overlays

This is similar to an optimization done in PhysicalModelLayer::Paint in the engine

This reverts commit e13e7806.

Turns out that with this patch, we aren't actually catching all
errors. For example, `flutter analyze --flutter-repo --watch` didn't
report errors in `dev/devicelab/test/adb_test.dart`.