This reverts commit 3e265e9e.

Rather than pre-compute Xcode install path, version, and EULA status,
compute and cache on demand.

This reverts commit bb8e2a7c.

Triggers a doctor failure on the Mac chromebots.

Rather than pre-compute Xcode install path, version, and EULA status,
compute and cache on demand.

Picks up primarily stability fixes.

* Provide haptic/acoustic feedback for tap & long-press on Android

* review comments

* fixed example code

* review comments

* comment fix

The main purpose of this PR is to make it so that when you set the
initial route and it's a hierarchical route (e.g. `/a/b/c`), it
implies multiple pushes, one for each step of the route (so in that
case, `/`, `/a`, `/a/b`, and `/a/b/c`, in that order). If any of those
routes don't exist, it falls back to '/'.

As part of doing that, I:

 * Changed the default for MaterialApp.initialRoute to honor the
   actual initial route.

 * Added a MaterialApp.onUnknownRoute for handling bad routes.

 * Added a feature to flutter_driver that allows the host test script
   and the device test app to communicate.

 * Added a test to make sure `flutter drive --route` works.
   (Hopefully that will also prove `flutter run --route` works, though
   this isn't testing the `flutter` tool's side of that. My main
   concern is over whether the engine side works.)

 * Fixed `flutter drive` to output the right target file name.

 * Changed how the stocks app represents its data, so that we can
   show a page for a stock before we know if it exists.

 * Made it possible to show a stock page that doesn't exist. It shows
   a progress indicator if we're loading the data, or else shows a
   message saying it doesn't exist.

 * Changed the pathing structure of routes in stocks to work more
   sanely.

 * Made search in the stocks app actually work (before it only worked
   if we happened to accidentally trigger a rebuild). Added a test.

 * Replaced some custom code in the stocks app with a BackButton.

 * Added a "color" feature to BackButton to support the stocks use case.

 * Spaced out the ErrorWidget text a bit more.

 * Added `RouteSettings.copyWith`, which I ended up not using.

 * Improved the error messages around routing.

While I was in some files I made a few formatting fixes, fixed some
code health issues, and also removed `flaky: true` from some devicelab
tests that have been stable for a while. Also added some documentation
here and there.

I got a bit confused by these comments when trying to debug this code,
let's try clearing them up a little.

Fixes https://github.com/flutter/flutter/issues/10911

https://github.com/flutter/flutter/issues/10650

Fixes #10929

* Add hasAGoodToStringDeep and equalsIgnoringHashCodes methods.

Methods simplify testing of toStringDeep calls and other cases where
methods return strings containing hash codes.

This allows us to take advantage of improved command-line tooling (e.g.,
improvements in device listing in Instruments). Now that the engine is
built with Xcode 8 and the framework is tested against Xcode 8, this
reduces the set of configurations we need to support to allow us to
focus on the supported ones: Xcode 8 and Xcode 9.

...and make one of the comments accurate by fixing the code. Turns
out I forgot to add the 'silent' argument when I changed that comment.

This print statement provides no value to the user.

https://github.com/flutter/flutter/issues/10940

The upstream fix is: https://github.com/dart-lang/usage/commit/021664efd35d563ee21eadbed40af6b5e8e23b2e

* Revert "Revert "Change all ocurrences of '$runtimeType#$hashCode' to use the idAndType method. (#10871)" (#10880)"

This reverts commit ceb814aa.

Revert "Change all ocurrences of '$runtimeType#$hashCode' to use the idAndType method. (#10871)" (#10880)

This reverts commit d46e208b.

* Change all instances of '$runtimeType#$hashCode' to use the describeIdentity method.

The describeIdentity method generates a shorter description with a consistent length
consisting of the runtime type and the a 5 hex character long truncated
version of the hash code.

(The Flutter plugin will use this to update the UI with test progress.)

Going forward, Android support libraries are published on maven (instead of bundling them with the SDK). Many plugins depend on these. To avoid requiring plugin users to add the maven repository to their app this change adds the repository to the template for `flutter create`.

This also bumps the support-annotations dependency to 25.4.0 (which also requires the new maven repository).

Fixes https://github.com/flutter/flutter/issues/10541

* Add version information to dartdoc footer

* Add final to variable declaration

* Drop toString()