Fixes #18829

Fixes https://github.com/flutter/flutter/issues/18007

This is an attempt to reland #18488 with less breakage on macOS.

* Roll to 549c855e89341b97436b3417542fc8f997492df7

* Clean up return void - see https://github.com/dart-lang/sdk/issues/33218

This reverts commit 77508722.

Add flutter tool support for creating app-specific VM snapshots.

(second attempt)

fuchsia_tester.dart still assumes Dart 1. Previously, it ran tests directly
from source, flutter_platform.dart automatically runs a kernel compile when
operating in Dart 2 mode, but this assumes a functional Dart SDK is available
in the artifacts directly, and fuchsia_tester.dart mocks out the artifacts
directory with an empty temp dir.

Remaining work is:
1. Get the frontend server building as a dependency on Fuchsia.
2. Patch fuchsia_tester.dart to use a valid Dart SDK and frontend server.

This also reverts migration to Dart 2 typedef syntax.

This reverts commit 6c56bb24. (#18362)
This reverts commit 3daebd05. (#18316)

Now that Dart 1 is turned off, reapplying my change to turn on the prefer_generic_function_type_aliases analysis option, and fix all the typedefs to Dart 2 preferred syntax.

Also eliminated the unused analysis_options_repo.yaml file and turned on public_member_api_docs in analysys_options.yaml.

No logic changes, just changing the typedef syntax for all typedefs, and updating analysis options.

Fingerprinter.doesFingerprintMatch() now returns false rather than
throwing if a depfile is malformed.

* It's time to #deleteDart1 (#18293)

Eliminates support for Dart 1 in flutter_tools, and drops our Dart 1
benchmarks. All commands now run in Dart 1 mode only.

Eliminates --preview-dart-2 / --no-preview-dart-2 support.

* Fix indentation, remove no longer necessary .toList()

* Only push udpated kernel if >0 invalidated srcs

Several benchmarks started failing during kernel compile:
1. Timeouts:
   * commands_test
   * hot_mode_dev_cycle__benchmark
   * run_machine_concurrent_hot_reload
   * service_extensions_test

2. Kernel compiler crash:
   * hot_mode_dev_cycle_linux__benchmark
   * routing_test

3. Unexpected termination:
   * hot_mode_dev_cycle_win__benchmark

This reverts commit ed63e708.

Eliminates support for Dart 1 in flutter_tools, and drops our Dart 1
benchmarks. All commands now run in Dart 1 mode only.

Eliminates --preview-dart-2 / --no-preview-dart-2 support.

This reverts commit 4f1b6604.

Revert "Update typedef syntax to use Function notation and turn on lint for old notation. (#18035)" (#18041)

This reverts commit 32586020.

Fixes #18028

Just changes typedef declarations, no logic changes.

* Search for a suitable ARM sysroot instead of hardcoding it;
* Add facility to explain why NDK was not found;

Further digging revealed that the reason --no-sim-use-hardfp was
required to be specified explicitly was that Android engine gen_snapshot
binaries are built on Windows with target_os=win.

This reverts #17147, which was safe under the assumption that
getArtifactPath() returns a platform-specific gen_snapshot instance
(which have the correct default set for this flag) -- it turns out that
though we pass the platform to getArtifactPath(), we always return the
host gen_snapshot for Android.

A followup patch will update getArtifactPath and revert this patch.

Previously, in non-release (i.e. profile) AOT builds, we were setting
--no-checked and --conditional_directives flags. --no-checked is the
default, and we don't make use of conditional directives in Flutter.

Allows users of Fingerprinter to filter the set of paths collected from
the explicitly-specified paths and those collected from depfiles.

In some cases, depfiles are emitted with files that are not present on
the local disk (e.g. the frontend compiler currently emits buildbot
paths for the dart core libraries and dart:ui). These files will not
materially affect whether we need to re-run a build action for which
they are inputs, since they're not present in the filesystem and
therefore cannot change.

This replaces the --prefer-shared-library flag, which falls back to
regular (non-shared-lib) compile if the NDK is not found, with the
--build-shared-library flag, which exits with an error message if the
NDK is not found.

This simplifies the set of allowed code paths through AOT compile,
resulting in better testability and easier-to-follow logic. It also
results in more predictable behaviour for continuous integration and
other scenarios.

We previously blocked iOS AOT builds, but Android debug builds are
always JIT builds.

This change adds support for armv7, arm64, and universal iOS apps.

This change eliminates iOS target architecture hardcoding (previously
arm64 only) and uses the target architecture(s) specified in Xcode's
ARCHS setting ('Architectures' in Xcode Build Settings).

For universal binaries, set ARCHS to its default value, $(ARCHS_STANDARD).

Note that after changing the architecture in Xcode, developers should
run 'pod install' from the ios subdirectory of their project. A separate
change (that will land before this one) will add support for
automatically detecting project file and Podfile changes and re-running
pod install if necessary.

This change also adds an --ios-arch option to flutter build aot. In iOS
AOT builds (in profile and release mode), this dictates which
architectures are built into App.framework. This flag should generally
be unnecessary to set manually since flutter build aot is typically only
invoked internally by flutter itself.

The new values are not ready for use yet inside Google

* Roll engine to e976be13c51448f89107d082ec81e2b6731671fa

* move away from deprecated constants

Adds a Fingerprinter utility class that can be used to compute unique
fingerprints for a set of input paths and build options, compare to the
output of a previous run, and skip the build action if no inputs or
options have changed. The existing Fingerprint class still does all the
heavy lifting. Fingerprinter adds common operations such as
reading/writing/comparing fingerprints and parsing depfiles.

This migrates existing uses of Fingerprint over to Fingerprinter.

This also adds better fingerprinting to AOT snapshotting, which
previously failed to include several options in its fingerprint
(--preview-dart-2, --prefer-shared-library).

ProcessResult.stdout has static type dynamic so for
inference to infer proper type argument for the map
invocation we need to cast stdout to String explicitly.

Fixes #17163

Previously, we were incorrectly passing --vm_snapshot_data and
--isolate_snapshot_data options to gen_snapshot in assembly AOT builds.
These only make sense in AOT blob snapshot mode (alongside
--vm_snapshot_instructions and --isolate_snapshot_instructions).

There's very little code-sharing between the two, and what little there
is is concentrated in the GenSnapshotClass and the fingerprint
reading/writing utility methods.

This de-duplicates assembly AOT configuration between Android and iOS,
and makes it easier to adjust parameters for 32-bit iOS (which, like
32-bit Android, requires --no-integer-division) in an upcoming patch.

This is now derived automatically from the target platform by
gen_snapshot.

iOS debug builds always run in interpreted mode whether on device or on
simulator. In both cases, we can skip snapshotting and link against an
empty App.framework. Previously, we did this for iOS simulator builds.
This does the same for device builds.

Previously, debug iOS builds used gen_snapshot to generate a core
snapshot, then used 'xxd' to generate C files containing the snapshot
data in buffers named kDartVmSnapshotData and kDartIsolateSnapshotData,
which are then compiled/linked into App.framework. This is unnecessary
since the VM compiled into Flutter.framework already contains this data.