In long lists this resulted in the dropdown scrolling to the very last
item in its list. Now clamping the value at `0.0`. Added a test to
verify that the selected item aligns with the button to test the offset.

Fixes flutter/flutter#15346

Make platform_channels_swift use more idiomatic Swift

* Remove semicolons.
* `if (condition)` => `if condition`.
* `Class.init(...)` => `Class(...)`.
* Remove `break` statements from `switch` cases.
* Remove some unnecessary uses of `self`.

* remove _ListenerMixin, which provides dubious value

* remove trailing whitespace

* Fix xcode_backend.sh script to support add2app

* Fix ios deployment target. Too old for new Xcode.

* Fix ios host app

* Register plugins with Flutter view

A dSYM file is created for the stripped `App.framework` and placed at `build/aot/App.dSYM`.

Reduces `App.framework` for Flutter Gallery by 6MB uncompressed, minus 23%.
Reduces `App.framework` for Hello World by 1.6MB uncompressed, minus 22%.

Fixes #4287.
Fixes #18693.
Helps with #21813.
See also #12012.

This change depends on https://dart-review.googlesource.com/c/sdk/+/76306.

* Roll Dart to 4cf2d3990bac1f1df2f524899e1560a3683f3133

Included CLs:

4cf2d3990b [VM runtime] Store Smi instance type in type test cache when using the interpreter.
a6b1a99f4c Make mixins abstract by default
ab305f2f26 Recover from duplicated declarations
4e32a356e0 Ignore synthetic elements created by the parser
fc04f56430 [infra] Remove deleted Dart 1 builders (app/precomp) from the test matrix
8477dc2131 Update status after 570fd5a7884
1652850381 Compute static types during impact computation
b4341f02db Remove unneeded method rti need
570fd5a788 Error on re-export, export and import of libraries with same name.
4b312b2b8c Support multiple superclasses in the mixin `on` clause.
8debb4e9db [fuchsia] Add zx_vmo_replace_as_executable calls
d34337aa2d Ignore noSuchMethod() for the purpose of searching concrete member implementations.
b6284b41e3 Revert "[VM] Dart_Initialize no longer crashes after Dart_Cleanup"
94481adbd4 [vm] Only include debugger/profiler slots in RawCode in product mode.
519ee905f9 [VM] Dart_Initialize no longer crashes after Dart_Cleanup
53497549ab [vm] Specialize 'new List()' on kernel AST
afd4cc9d1a [vm/tfa] Infer concrete class of int literals in TFA
a4d48f49e7 [vm/tfa] Infer concrete class of string literals in TFA
9106228a55 [vm, dwarf] Set default_is_stmt to true for compatability with dsymutil.
6ce0dc0006 dartfix stub implementation
e4eb2437b8 Look into superclassConstraints while searching for a member in interfaces.
95d37b0921 Revert "Implement inheritance/override checks from the spec."
355c73d4ee [VM] Remove support for option --no-preview-dart-2
95b8a19a20 Mixin declarations don't have supertype, fix isMoreSpecificThan().
e9586a5d14 [vm] Update workaround for Android Kernel bug (b089d4f).
ef7d144bc7 Add regression test for issue 34392.
56f6c52d58 large_class_declaration_test is slow now.
0ac3b8fff9 [fuchsia] Add missing vm:entry-point annotation
19e844ed5b [dart/fuzzing] Use current directory as SDK top (by default)
58e44c1400 Don't use ClassElementImpl for now in override checking.
62d154f6a3 [vm/bytecode] Record null-initialized fields in bytecode
70cc34df21 Custom format errors and exceptions to show traces
95831136b4 Fix NPE when accessing superclass
836a1d7a88 Implement inheritance/override checks from the spec.
d07039782a Remove redundant resolution
dba8b37d38 [vm] Benchmark for reading kernel bytecode

* Move one revision later.

Rationale:
Relatively harmless change, but at least has
builds (force builds on the older revision
will take a while again).

* Add tab bar theme.

* Add tab bar theme.

* Add tests, pass context to getters.

* update goldens from linux box

* update goldens from linux box

* Added new golden test, addressed comments

* override hashCode and == in TabBarTheme

* Fix comment typos

* Addressed Hans' comments.

* Formatting changes

* [TabBarTheme] Fixed spacing

* [TabBarTheme] Update goldens version to latest commit

It turns out that #21888 didn't really fix the link, because *this* is the README used by dartdoc for flutter.

* Prototype

* Fix paths to Flutter library resources

* Invoke pod install as necessary for materialized modules

* Add devicelab test for module use on iOS

* Remove debug output

* Rebase, reame materialize editable

* Add devicelab test editable iOS host app

* Removed add2app test section

* Refactor of cupertino/material/widgets app

* update docs 

* Update tests for const

MaterialPageRoute transitions are now defined by the Theme. Added (optional) support for Android P style page transitions.

Swap out the moon emoji used for progress spinner for a single-cell character.

The moon emoji looked cool, but couldn't be used because of bugs in xterm.js, used for VSCode's terminal, among others. The moon emoji is two character cells wide, but xterm.js doesn't advance by two cells when it adds the emoji, but does go back by two when it backspaces.

This changes us to a different character animation (dots) that is only one cell wide, and so doesn't have this problem.

This reverts commit 61cf946b.

* Make CupertinoApp and MaterialApp both use WidgetsApp for Navigator

* Make CupertinoApp and MaterialApp const constructors

* Make WidgetsApp routes aware

* Update tests

This will now make it so that the Dart VM class returns any Isolate that
matches the passed Pattern, without checking for any specific strings
like "main()"

This causes the search to skip over Isolates that would have matched.

https://github.com/flutter/engine/compare/f4aadb11cf13...74625aed323d

git log f4aadb11cf13..74625aed323d --no-merges --oneline
74625aed3 Keyboard padding detection heuristic to distringuish when to include bottom inset. (flutter/engine#6288)
617b122bd Roll Dart to a2eb050044eec93f0844667b8b6132e858467e4e. (flutter/engine#6321)


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Documentation for the AutoRoller is here:
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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.

https://github.com/flutter/engine/compare/d5deda95176e...f4aadb11cf13

git log d5deda95176e..f4aadb11cf13 --no-merges --oneline
f4aadb11c Change FlutterDartProject to keep precedence when looking for the ass… (flutter/engine#6305)


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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.

https://github.com/flutter/engine/compare/17f8b2f32ae4...d5deda95176e

git log 17f8b2f32ae4..d5deda95176e --no-merges --oneline
d5deda951 Roll src/third_party/skia 0a3864651457..a9adb6f03525 (2 commits) (flutter/engine#6320)


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

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https://github.com/flutter/engine/compare/57fd394e59b8...17f8b2f32ae4

git log 57fd394e59b8..17f8b2f32ae4 --no-merges --oneline
17f8b2f32 Roll src/third_party/skia c955a1645148..0a3864651457 (1 commits) (flutter/engine#6319)
bef460999 Roll src/third_party/skia bdb32d17999e..c955a1645148 (2 commits) (flutter/engine#6318)
6c17ce74e Roll src/third_party/skia 937348d4d442..bdb32d17999e (1 commits) (flutter/engine#6317)
94c591a1d Roll src/third_party/skia 175b587a634d..937348d4d442 (1 commits) (flutter/engine#6316)
e82db8668 Remove the unused Mac Desktop shell. (flutter/engine#6314)


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

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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.

https://github.com/flutter/engine/compare/f3a3d0ce7f0b...57fd394e59b8

git log f3a3d0ce7f0b..57fd394e59b8 --no-merges --oneline
57fd394e5 Ensure that objects on stack that close traces have unique variable names. (flutter/engine#6298)


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* expose the debugProfileBuildsEnabled flag as a service extension

* fix tests

* review comments

* remove a new keyword

* test fixes

* review comments

* Improve documentation and clean up code.

* Remove "Note that".

The phrase "note that" is basically meaningless as a prefix to an
otherwise fine sentence.

https://github.com/flutter/engine/compare/cc3009cb4ea9...f3a3d0ce7f0b

git log cc3009cb4ea9..f3a3d0ce7f0b --no-merges --oneline
f3a3d0ce7 Roll src/third_party/skia 11f4994b84e1..175b587a634d (1 commits) (flutter/engine#6313)
19ac3e1ac Roll src/third_party/skia 358558a4cecc..11f4994b84e1 (2 commits) (flutter/engine#6312)
7648d21b0 Dart SDK roll for 2018-09-21 (flutter/engine#6311)
5b8e8c328 Make FlutterStandardCodec handle writing NSData (flutter/engine#6207)
02901b78c Decouple PlatformViewsController from FlutterView. (flutter/engine#6303)


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Unbreak build.

git log a8890fdccd667d0bf0fa0a81ac350dadef60bd6c..cc3009cb4ea920863b23937ef569327880b01fba --no-merges --oneline
cc3009cb4 Revert 'Dart SDK roll for 2018/09/20' 8471862c (#6309)
bbdf7c158 Revert "Fix a compilation problem when using iPhoneOS12.0sdk(Xcode10) && clang version 7.0.0." (#6307)
dea09212c Roll src/third_party/skia c25f440d537e..358558a4cecc (17 commits) (#6308)
d29c7db76 Add logging if FlutterDartProject fails to load the application kernel snapshot (#6257)
2a1debfcc Update deprecated subtags from language subtag registry. (#6280)
540cd9626 Add Xib splashscreen support (#6289)
05f21e63a (main) Fix a compilation problem when using iPhoneOS12.0sdk(Xcode10) && clang version 7.0.0. (#6279)
ca6f10389 Roll src/third_party/skia d842557c0724..c25f440d537e (10 commits) (#6304)
3b46705db Roll src/third_party/skia 38ca6d509d9f..d842557c0724 (5 commits) (#6302)
0c166fe3f Roll src/third_party/skia 05cf051f0252..38ca6d509d9f (1 commits) (#6301)
cf0fbadce Roll src/third_party/skia 44c6167c4125..05cf051f0252 (4 commits) (#6299)
2ec20aaeb Remove bottom safe-area padding when keyboard up (#6297)

* add a test for single- and multi-line paragraph layout

* use flutter_test

* use closeTo for double comparison