* Update project.pbxproj files to say Flutter rather than Chromium

Also, the templates now have an empty organization so that we don't cause people to give their apps a Flutter copyright.

* Update the copyright notice checker to require a standard notice on all files

* Update copyrights on Dart files. (This was a mechanical commit.)

* Fix weird license headers on Dart files that deviate from our conventions; relicense Shrine.

Some were already marked "The Flutter Authors", not clear why. Their
dates have been normalized. Some were missing the blank line after the
license. Some were randomly different in trivial ways for no apparent
reason (e.g. missing the trailing period).

* Clean up the copyrights in non-Dart files. (Manual edits.)

Also, make sure templates don't have copyrights.

* Fix some more ORGANIZATIONNAMEs

* CupertinoTabBar

* CupertinoButton

* update

* review

(Breaking Change) Move some hardcoded pixel values to reusable constants.

* Fixes offset and unblocks roll

* Fixes cursor on iOS devices

* Future<void> main

* Future<void>.delayed

* prefer_void_to_Null

* address review comments

* enable lint unnecessary_new

* fix tests

* fix tests

* fix tests

It was causing problems rolling Flutter into Fuchsia

* re-enable lint unnecessary_const

* remove trailling whitespaces

* remove unnecessary const (after merge)

This reverts commit cc1cf13e.

fixes #11992 

* create auto back button behaviour

* cosmetic fidelity

* tests

* review

* document new icon

Fix a bunch of obvious RTL bugs from code inspection.

* Do not schedule animation if already at the target value

* Partially fixes https://github.com/flutter/flutter/issues/11495.
* Also includes a fix for Cupertino button to always run the tap animation even if the finger is immediately lifted from the screen (uncovered by a test failure).

* refactorings

* more tests

* test clearifications

* remove Listener

* fix lints

* fix async issue

Add Diagnosticable base class and documentation

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

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

Move some Cupertino colors to a common file. 

Create a CupertinoTabBar widget to mimic iOS looks

backgroundColor -> color
backgroundImage -> image
BackgroundImage -> DecorationImage

* more widget const constructors

* prefer const constructors

* address review comments

Rename State.config to State.widget
Rename State.didUpdateConfig to State.didUpdateWidget
Renamed all State subclasses' local variables named config to something else

* Allowing overrides to the activeOpacity of the button

* adding tests

* fix

* fixing animation

* fixes

* moar fixes

The recommended minimum tappable area is actually 44.0pt according to the [iOS Human Interface Guidline](https://developer.apple.com/ios/human-interface-guidelines/visual-design/layout/).

> Provide ample spacing for interactive elements. Try to maintain a minimum tappable area of 44pt x 44pt for all controls.

I've also added an override to allow for flexibility in situations where designers get naughty and have a desire to make everything super small.

* Use exact Ahem and exact dimensions for test

* use ‘px’ everywhere