[flutter_tool][gallery] Standardize target platform override behavior in tool and update flutter gallery to support it (#46206)

[flutter_tool] remove ability to disable Fingerprinter with DISABLE_FLUTTER_BUILD_CACHE env variable (#46913)

[flutter_tool] fix NPE in daemon caused by returning null connection info from experimental web runner (#46909)

* Prposal for supporting URL tunnelling

* Update daemon.md

* Add the ability for daemon to call clients to expose URLs

* Fix dwds mock in web_fs tests

* Fix type error

* Remove build_runner import from run

* Move appStartedTime back to after the app has started

* Remove nested DI scope and pass urlTunneller down

* Fix import

* Tweak TODO

* Fix existing tests

* Fix spec to use result instead of params for response object

* Fix exposeUrl to use a url field, as spec'd

* Test that the daemon's exposeUrl sends a request and handles the response

The variable debugDisableShadows wasn't reset before each test, so the
output of the test is different depending on whether the previous test
has passed.

* Make golden test timeout longer, some tests are flaky if the timeout is too short

* Enable some golden tests for web

* ExpandIcon should use the size parameter

This reverts commit 43530b80.

This reverts commit 86dd664f.

https://github.com/flutter/engine/compare/12bf95fd49b7...140818a71532

git log 12bf95fd49b7..140818a71532 --first-parent --oneline
2019-12-10 skia-flutter-autoroll@skia.org Roll fuchsia/sdk/core/linux-amd64 from Zkpa_... to nqJnP... (flutter/engine#14274)
2019-12-10 skia-flutter-autoroll@skia.org Roll src/third_party/skia e56cc054dbae..ab26643258ad (3 commits) (flutter/engine#14273)


If this roll has caused a breakage, revert this CL and stop the roller
using the controls here:
https://autoroll.skia.org/r/flutter-engine-flutter-autoroll
Please CC franciscojma@google.com on the revert to ensure that a human
is aware of the problem.

To report a problem with the AutoRoller itself, please file a bug:
https://bugs.chromium.org/p/skia/issues/entry?template=Autoroller+Bug

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

https://github.com/flutter/engine/compare/2805da9e5dd2...12bf95fd49b7

git log 2805da9e5dd2..12bf95fd49b7 --first-parent --oneline
2019-12-10 skia-flutter-autoroll@skia.org Roll src/third_party/skia 095d2468a075..e56cc054dbae (4 commits) (flutter/engine#14270)
2019-12-10 hterkelsen@users.noreply.github.com Add support for platform views in the CanvasKit backend (flutter/engine#14263)


If this roll has caused a breakage, revert this CL and stop the roller
using the controls here:
https://autoroll.skia.org/r/flutter-engine-flutter-autoroll
Please CC chinmaygarde@google.com on the revert to ensure that a human
is aware of the problem.

To report a problem with the AutoRoller itself, please file a bug:
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Documentation for the AutoRoller is here:
https://skia.googlesource.com/buildbot/+/master/autoroll/README.md

https://github.com/flutter/engine/compare/b9080c92b98a...2805da9e5dd2

git log b9080c92b98a..2805da9e5dd2 --first-parent --oneline
2019-12-10 50856934+nturgut@users.noreply.github.com Enable web engine unit tests on Firefox (flutter/engine#14267)
2019-12-09 cstout@google.com [shell][fuchsia] Add lib/async/default.h
2019-12-09 skia-flutter-autoroll@skia.org Roll src/third_party/skia c937bc50250d..095d2468a075 (7 commits) (flutter/engine#14269)
2019-12-09 hterkelsen@users.noreply.github.com Use the versioned canvaskit from unpkg. (flutter/engine#14264)


If this roll has caused a breakage, revert this CL and stop the roller
using the controls here:
https://autoroll.skia.org/r/flutter-engine-flutter-autoroll
Please CC chinmaygarde@google.com on the revert to ensure that a human
is aware of the problem.

To report a problem with the AutoRoller itself, please file a bug:
https://bugs.chromium.org/p/skia/issues/entry?template=Autoroller+Bug

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

b9080c92b Roll src/third_party/dart 7fcaafbb3e..8b8894648f (1 commits) (flutter/engine#14266) (#46645)


https://github.com/flutter/engine/compare/a614c0a2d45f...b9080c92b98a

git log a614c0a2d45f..b9080c92b98a --first-parent --oneline
2019-12-09 bkonyi@google.com Roll src/third_party/dart 7fcaafbb3e..8b8894648f (1 commits) (flutter/engine#14266)


If this roll has caused a breakage, revert this CL and stop the roller
using the controls here:
https://autoroll.skia.org/r/flutter-engine-flutter-autoroll
Please CC chinmaygarde@google.com on the revert to ensure that a human
is aware of the problem.

To report a problem with the AutoRoller itself, please file a bug:
https://bugs.chromium.org/p/skia/issues/entry?template=Autoroller+Bug

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