* lint unnecessary_new on samples

* fix tests

* Added music_note icon

This reverts commit 343b5703.

Reverting because the assert introduced in framework.dart(inheritFromElement) is breaking certain Mulligan pages. @hixie suspects it might be due to global keys.

* Update goldens for flutter/engine#6184

* Roll engine to 9b297b3b51228...

* Add build test for Flutter codelabs

* Fix indentation in build test script

* Correct filename for the codelabs build test run by travis

* Change if statement to elif

* Replace echo statements with set -x

* Add BSD-style license

* Add codelabs build test to Cirrus

* Remove codelabs_build_test from Travis.

* Remove codelabs_build_test from travis_script.sh

* Update documentation for codelabs_build_test.sh

* Update readme for build test

* Add link to open a new issue to MDC-Flutter

* Add phrase to address "if you think you really need to break this test, please escalate this"

https://github.com/flutter/engine/compare/de4c7a53f21c...5f61056946ef

git log de4c7a53f21c..5f61056946ef --no-merges --oneline
5f6105694 Revert "Dart SDK roll for 2018/09/04 (#6161)" (flutter/engine#6183)
897178cc3 Roll src/third_party/skia 71f8475a0dba..33d3d31a7e28 (6 commits) (flutter/engine#6182)
1768bedcf Roll src/third_party/skia ffbcc3fadfa1..71f8475a0dba (3 commits) (flutter/engine#6181)
ade0f2230 Remove unused file picture_serializer. (flutter/engine#6179)
572753fb1 Roll src/third_party/skia 343553a1fe9e..ffbcc3fadfa1 (6 commits) (flutter/engine#6178)
108e0a64e Add transparency helpers to FlutterView.java (flutter/engine#6172)
f6ad3e096 Roll Tonic (flutter/engine#6177)
a0f30b3b0 Roll src/third_party/skia 9d1c88d9912d..343553a1fe9e (16 commits) (flutter/engine#6175)
e6d9b34a8 Remove the old location of the ICU data asset (flutter/engine#6170)
9f0ad8b79 Fixes negative end selection offset. (flutter/engine#6171)
0981731fd Enable transparent FlutterViews (flutter/engine#6163)
3a7d0b559 Roll buildroot to 7aadfaf196f9cd8a299f9ad78fab63362800466d (flutter/engine#6169)
564d214b7 Roll src/third_party/skia d0f0cb8ffc5e..9d1c88d9912d (12 commits) (flutter/engine#6168)
6af60d716 Remove obsolete discovery mechanism from FlutterView (flutter/engine#6157)
b22badf1d Dart SDK roll for 2018/09/04 (flutter/engine#6161)
6d0fbc7eb Roll src/third_party/skia 9478f7a38e6c..d0f0cb8ffc5e (1 commits) (flutter/engine#6167)
5063a8a5b Roll src/third_party/skia 72a02112a99f..9478f7a38e6c (1 commits) (flutter/engine#6166)
19a3bc8e1 Roll src/third_party/skia 85f4e40c5481..72a02112a99f (1 commits) (flutter/engine#6165)
9643a50ac Roll src/third_party/skia fddc6fa394cb..85f4e40c5481 (1 commits) (flutter/engine#6164)
6ad3183b1 Fix windows build. (flutter/engine#6162)
30af2f299 Roll src/third_party/skia e486bbaae296..fddc6fa394cb (2 commits) (flutter/engine#6159)
b32ceafb1 Add some more logs for diagnosing screenshot failures (flutter/engine#6156)
c173655b2 Roll src/third_party/skia b84576af0a43..e486bbaae296 (9 commits) (flutter/engine#6155)
aaf98fbfe Use double multiplication by a scale instead of 3 divides for speed. (flutter/engine#6154)
593ed5914 Revert "Use Skia normalize again after Skia precision fix. (#6121)" (flutter/engine#6122)
137389a85 Roll src/third_party/skia a45e1a71f548..b84576af0a43 (16 commits) (flutter/engine#6153)
f89a386a1 Roll src/third_party/skia cff3fd834ca8..a45e1a71f548 (1 commits) (flutter/engine#6152)
b0b8daa7b Unregister onFrameAvailable callbacks when a TextureEntry is released. (flutter/engine#6079)
2dc8271a4 Roll src/third_party/skia 24e58341fbcd..cff3fd834ca8 (1 commits) (flutter/engine#6151)
eea3a21e1 Roll src/third_party/skia bf67741140fd..24e58341fbcd (2 commits) (flutter/engine#6148)
bdcbe801a Roll src/third_party/skia 88119de2b849..bf67741140fd (1 commits) (flutter/engine#6147)

The AutoRoll server is located here: https://autoroll.skia.org/r/flutter-engine-flutter-autoroll

Documentation for the AutoRoller is here:
https://skia.googlesource.com/buildbot/+/master/autoroll/README.md

If the roll is causing failures, please contact the current sheriff, who should
be CC'd on the roll, and stop the roller if necessary.

* Scale high-pixel-ratio images with BoxFit.none/BoxFit.scaleDown correctly

* add test cases for image scale

* make analyzer happy

* Make sure that test images always have a scale to make all tests pass

* add a new author

* use new keyword in tests

This recognizer can be passed in AndroidView's gesureRecognizers when we
want all touch events in the view bounds to be immediately dispatched
to the Android view.

* monodrag fix

* added a test

* added test and changes

* fixed import

* removed comments

--preview-dart-2 is no longer necessary as it is now the default for the
standalone Dart VM.

I'm working on fixing up all tests that rely on fs.currentDirectory to allow us to run concurrently. This one proved to be really tricky because it calls a lot of code and spawns multiple processes that have a mix of absolute and relative paths passed to them. I managed to handle some of it with a ChrootFileSystem, but the paths passed to the external processes were wrong.

The functionality here is covered by all of the integration tests that use flutter_tester that were added after this, including flutter_run_test.dart, lifetime_test.dart etc. in this same folder but because they're run through `flutter run` as a separate process they get to set their own working directories without affecting other tests if run concurrently.

The average frame time of page transitions on Moto G4 is now very
close to 16ms (the last 10 measurements on our dashboard are
between 15.5ms to 16.7ms and half of them are below 16ms).

It is now much faster than when we disabled it (which was at about
35ms). So I think that we should be able to enable it by default.
I'll leave the flag there until we implement the retained rendering
to bring the frame time comfortably below 16ms.

See https://github.com/flutter/flutter/issues/13736

Setting the default clip behavior made bottom app bar to no longer clip
its children.
With this parameter users could opt-in to clipping.

* Add a detach command to detach without terminating (#21376)

* Add a detach command to detach without terminating

Fixes #21154.

* Bump protocol version for app.detach

* Tweak to detach/quit text

* Change logPrefix to named param

* Fix the text that the devicelab attach test looks for

* Rename test file

* Fix detection to work regardless of whether there are other devices

On Windows we get one message, but on Mac we get another (because of the Simulator always being available).

Revert "Allow FlutterTester to be provided with the working directory for execution (#21119)" (#21453)

This reverts commit 857bdc7a.

* Allow FlutterTester to be provided with the working directory for execution

Previously this test set fs.currentDirectory which prevents running tests concurrently. This allows setting the working directory for a FlutterTester in the cosntructor (optionally) and passes it through from the test (without setting fs.currentDirectory).

* Remove trailing whitespace

* Add a detach command to detach without terminating

Fixes #21154.

* Bump protocol version for app.detach

* Tweak to detach/quit text

* Change logPrefix to named param

Move asset_bundle_package_test to MemoryFileSystem to avoid setting fs.currentDirectory in tests (#21427)

* Update asset_bundle_package_test to use MemoryFileSystem

This updates all tests in this file to use a memory filesystem (same as I did for asset_bundle_package_font_test) based on the current platform.

There were already a few minor tests at the bottom using a MemoryFileSystem and being run for all platforms - however this complicated the shared code I changed above to support Windows natively so I changed them to also work the same as others (that is, they just run the native platforms so require running on all to get full coverage - though this is the case for almost all other tests anyway).

* Move fixPath to the correct place

* Add a failing test for #21418

* Filter workflows to only those applicable to the current platform

Fixes #21418.

* First step in Flutter Doctor refactor. Assigns categories to all validators.

* Revert "Roll engine e54bc4ea1832..a84b210b3d26 (6 commits) (#20453)"

This reverts commit 05c2880a.

* Split iOS and Android workflows into workflow and validator classes.

* Change ValidatorCategory to handle standalone validators that share a
category (e.g. IntelliJ).

Also make Android Studio and Android toolchain use separate categories.

At this stage, flutter doctor output matches what it was previously.
(The summary() method itself has not yet been changed )

* Change doctor summary code to support validator categories.

Output is still unchanged.

* Handle small formatting issues.

* Flip Flutter category's isGroup field to false until it's actually
needed.

* Revert auto-generated formatting changes to keep those lines from
muddying the pull.

* Small fixes pointed out by analyzer.

* Properly fix analyzer issues around const constructors.

* Small changes to address comments.

* Add tests to verify grouped validator behavior and validationtype
merging.

* Update doctor.dart

* Add comments for clarification.