Follow-up comments to #15984

* Revert "Revert "Move mockito to 3.0.0-alpha. (#15949)" (#15979)"

This reverts commit e59651f9.

* More thenReturn to thenAnswer when mocking Futures

* Revert "More thenReturn to thenAnswer when mocking Futures"

This reverts commit 194d2cf41754ad171efd6bb5898cf73bce5a75ab as we are reverting engine roll.

* Revert "Revert "More thenReturn to thenAnswer when mocking Futures""

This reverts commit 52c9e96b304b220f66d78a252fccea0c8e0ef24c.

* Add dependency override

* Fix issue

This updates AppContext per the recommendations in #15352

Fixes #15352

* Support for decimal and signed numeric keyboard

* Comments

* Rebase.

* Roll engine to dd6f46c485192f4506035088c9065b9f5dbba9ab

Type-related fixes in flutter_driver and fuchsia_remote_debug_protocol
tests.

Includes:
* Remove declaration for undefined GPUSurfaceGL::SelectPixelConfig (flutter/engine#4857)
* Vulkan swap chain setup no longer uses GrPixelConfig and doesn't incl…
* Revert dart roll 20180322 (flutter/engine#4855)
* Roll back pub upgrade. (flutter/engine#4854)
* Roll flutter 20180322a (flutter/engine#4852)
* Document Window.defaultRouteName a little better. (flutter/engine#4851)
* Roll dart to 95e9e890a9 (flutter/engine#4850)

Includes:
* Fix GPUSurfaceGL includes on Linux (flutter/engine#4849)
* Slightly improve the docs for the internal _futurize method (flutter/engine#4847)
* Fix supported color type check on iOS simulators (flutter/engine#4846)
* Fix GPUSurfaceGL includes on macOS (flutter/engine#4844)
* Handle Apple-specific GLES headers (flutter/engine#4843)
* [fuchsia] Fix up includes of Zircon headers (flutter/engine#4842)
* VulkanSurface and GPUSurfaceGL no longer use GrPixelConfig (flutter/engine#4814)

Includes:
* Roll Skia (flutter/engine#4841)

Includes:
* Provide asset lookup key on ios (flutter/engine#4817)
* Load kernel files from the script URI in the isolate create callback (flutter/engine#4828)
* Remove some unneeded profiling flags (flutter/engine#4827)
* Remove the canvas save/restore calls in Paragraph::Paint (flutter/engine#4822)

This caused a test failure in the integration_ui_ios devicelab test.

```
stdout: [   +3 ms] 00:02 [32m+0[0m: end-to-end test Ensure keyboard dismissal resizes the view to original size[0m
stdout: [+8129 ms] 00:11 [32m+0[0m[31m -1[0m: end-to-end test Ensure keyboard dismissal resizes the view to original size [1m[31m[E][0m[0m
stdout: [   +5 ms]   DriverError: Failed to fulfill Tap: Flutter application not responding
stdout: [        ]   Original error: TimeoutException after 0:00:07.500000: Future not completed
stdout: [        ]   Original stack trace:
stdout: [        ]   #0      FlutterDriver._sendCommand (package:flutter_driver/src/driver/driver.dart:324:18)
stdout: [        ]
stdout: [        ]   #1      FlutterDriver.tap (package:flutter_driver/src/driver/driver.dart:368:11)
stdout: [        ]
stdout: [        ]   #2      main.. (file:///[... snip ...]/flutter/dev/integration_tests/ui/test_driver/keyboard_resize_test.dart:34:20)
```

This reverts commit 067be92a.

This reverts commit a7e62258 as there are failing tests.

* Move mockito to 3.0.0-alpha.

This is needed so it matches mockito version used internally.

* Pick up +2 for the fixes

* Fix whenReturn in fuchsia_remote_debug_protocol

* more thenReturn becomes thenAnswer

* more thenReturn becomes thenAnswer

* more thenReturn becomes thenAnswer

Roll engine to version dd6f46c485192f4506035088c9065b9f5dbba9ab

* Address post-submit comments

* Added dispose protection for the animation controllers.

* android templates should add density and screenLayout to config changes

* update the rest of the manifests

* Remove tear-off mocking in refresh_test

* Comments

* Analyzer fix

* Final final final final mushroom mushroom!

* Fix for Dart 1 AND Dart 2 semantics; anonymous closure over tear-off

* Final final

* CONTRIBUTING.md: updates for Dart 2; move parts to flutter/engine

* address comments

* Add more doc linking the material and cupertino refresh controls

* review

* Re-enable usage of TransformLayers with text in RenderListWheelViewport

* add test

* linter fix

Adds a package that will support connecting to and debugging devices with multiple instances of the Dart VM, and operate on multiple Isolates and Flutter Views.

Currently supports connecting to all existing Dart VMs and extracting information about all Flutter Views running across each VM.

This is not a grand refactor yet, it's just cleaning up what we have
already, so that people who keep using this API (e.g. dialogs) have
something coherent to deal with.

The major changes are that Navigator and NavigatorState have the same
API now, that most of the examples use `<void>` instead of `<Null>`,
that the navigator observer can see replaces, and that the `settings`
is moved from ModalRoute to Route. I also cleaned up some of the API
documentation.

* use HttpOverrides and dart:io HttpClient in flutter

* add missing package:http dependency

* update flutter packages and remove comment about createHttpClient from flutter_test

* move byte loading logic to common class, move string parsing logic to base class

* addAll doesn't work for a Uint8List

* use bytes.setRange

* undo addition to hello_world

* add newline to end of binding.dart

* and a newline for hello world

* refactor to function and add tests

* address comments on unknown length case

* alignment

* sort alaphabetically

* rename convertResponse to consolidateClientHttpClientResponseBytes.  Add header

* fix alignment in test