/bin/sh, for example, doesn't support pushd/popd.

* Track widget creation locations.

* Analysis cleanup of the Dart in the Engine repo

* Update painting.dart

* Update painting.dart

* Introduce frontend_server that allows for interactive and batch modes.

Example of batch mode:
```
$ dart $HOME/p/f/t11/flutter/engine/src/flutter/frontend_server/bin/server.dart --sdk-root=$HOME/p/f/t11/flutter/engine/src/out/android_debug/flutter_patched_sdk --platform-kernel-dill=$HOME/p/f/t11/flutter/engine/src/out/android_debug/flutter_patched_sdk/platform.dill $HOME/p/f/t11/flutter/flutter/examples/flutter_gallery/lib/main.dart

out: result 79256789-598c-4909-a9e4-0ef36d4c26ba
out: 'State&TickerProviderStateMixin^#U0^' is exported from both 'package:flutter/src/widgets/animated_cross_fade.dart' and 'package:flutter/src/widgets/animated_list.dart'.
...
out: Superclass has no method named 'hitTest'.
out: 79256789-598c-4909-a9e4-0ef36d4c26ba $HOME/p/f/t11/flutter/flutter/examples/flutter_gallery/lib/main.dart.dill
$
```

Example of interactive mode - communication via stdin/stdout:
```
$ dart $HOME/p/f/t11/flutter/engine/src/flutter/frontend_server/bin/server.dart --sdk-root=$HOME/p/f/t11/flutter/engine/src/out/android_debug/flutter_patched_sdk --platform-kernel-dill=$HOME/p/f/t11/flutter/engine/src/out/android_debug/flutter_patched_sdk/platform.dill --incremental

out: Frontend server is ready.
in: compile abc.dart
out: result fd99c0f9-12bb-4083-818e-2521d454fdc8
out: fd99c0f9-12bb-4083-818e-2521d454fdc8 abc.dart.dill
in: accept
in: recompile kuka
in: 123.dart
in: 456.dart
in: kuka
out: result d12f8d05-6c79-44f7-a775-1d3469e1be53
in: quit
$
```

* Add test. Cleanup dependencies.

* One more test with mocks

* Remove platform-kernel option. Refactored CompilerOptions. Clean up comments.

* Update license

* Use Uri.base.resolve consistently. Ensure folder path for sdk root. Fix test.

* Fix main_dart for frontend_server build target

* Reintroduce .packages file, add README.md, revert changes to licenses_flutter

* Run analyzer on frontend-server. Update .packages deps so tests can be run too.

* Add analyzer options file

* Clean up dependencies

* Add frontend_server files to license file back

* Fix comment in analysis_options.yaml

* Run frontend_server tests in travis

* Update licenses

* Change a+x permission on travis/test.sh

* pub get before pub run test

* Fix path to when

* Clarify accept/reject instructions

* Formatting, fixed docs, style

* Update license script to skip .travis.yml, when/example. Update license file.

* Update style nits

* Fix license

* Trim license extracted text. Fix licenses

* Update licenses_third_party signature

* Few more tests

* Update dart license

* Update dart license

* Style changes. Fix return value for Future<Null>

* Remove the Point class.

* Add Size.contains and Rect.translate for consistency

* Make Offset and Size compare == with subclasses.

Without this we would break the _DebugSize hack.

* Fix copy/pasta

* Fix the examples in the engine repo

After this patch, we no longer link with Mojo. We still use some gn definitions
from //mojo to create Dart packages.

The buildbot and Travis are running inconsistent versions of the analyzer

This patch moves the geometry classes.

Change the "develop" runtime mode back to "debug" and rename the "debug" build configuration to "unoptimized" (#2669)