* Pre-Dart SDK roll engine revision

* Dart SDK engine roll for 2018-05-30.

Commits:

3b6caa3517b Split UnresolvedNameGenerator
f50873d3451 [fuchsia] Renaming component FIDL to fuchsia.sys.
13987b073d6 Add Forest method to access the name of a variable
declaration
3b86f823d0a [vm/corelib] Remove GrowableArrayMarker hack.
88127f10e4f Clean up num#toStringAsPrecision docs
1eb1885c62d tools/addlatexhash.dart: Remove unused import
03cb46a2290 [vm/perf] Fix JITDUMP integration.
9d9eff44c99 Support sharing function signatures in deferred parts for
fast startup
ae9f5d2a1b1 Add Forest API for logical expressions
66c590d3ad3 Add json/utf8 BOM support in changelog.
d116e62d76d Improve catch parameter recovery
aa8e2ee178d Revert "[vm] Add tests for determinism of script and AppJIT
snapshots."
ec47e524bc9 Switch to non-alpha versions for analyzer/front_end/kernel.
aac0478fada [vm] Add tests for determinism of script and AppJIT
snapshots.
6cc7aa803a1 Change names/declarations tasks in AnalysisDriver sync.
c30af41b96c Reapply "[mirrors] Add IsolateMirror.loadUri."
a40993a6aff Observatory strong mode fix: Fix incorrect types in
DebuggerStackElement.
0fdfc9aa3b6 Observatory strong mode fix: Add a needed implements clause.
209029ab8ee Observatory strong mode fix: Pass through a type parameter
in the implements clause for GuardedMock.
1d323687b39 Use selection to decide whether EXTRACT_LOCAL_VARIABLE and
EXTRACT_METHOD are available.

This makes it easier to run ios add2app apps with Flutter run.

* Expose Gradient.radial

* cleanup doc

* update tests, null check

* add asset images

flutter/engine@d174c4f Remove unnecessary saveLayer
flutter/engine@b41c2ae Roll src/third_party/skia 137b874..588f879 (6 commits)
flutter/engine@15be13d Roll src/third_party/skia 21ca043..137b874 (5 commits)
flutter/engine@dfb437a Roll src/third_party/skia 264182c..21ca043 (3 commits)
flutter/engine@abda89c Roll src/third_party/skia 09725b0..264182c (1 commits)
flutter/engine@0a47817 Roll src/third_party/skia 61f36d3..09725b0 (1 commits)
flutter/engine@a4f0cd7 Roll src/third_party/skia 8363be1..61f36d3 (8 commits)

This PR adds a SweepGradient class, extending Gradient to expose the engine's ui.Gradient.sweep shader.

Similar to LinearGradient and RadialGradient - SweepGradients can be used in a BoxDecoration or passed to a Paint's shader.

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.

Uses the `version` property from the `pubspec.yaml` file to set the corresponding fields in the `local.properties` file respectively in the `Generated.xcconfig` file.

The `--build-name` and `--build-number` options have changed. Now they trump the `version` property from the `pubspec.yaml` file.

If the `version` property is not set and the  `--build-name` and `--build-number` options are not provided, the build command will not change the `local.properties` / `Generated.xcconfig` file.

* Detect permissions issues running flutter on Windows

Fixes #17972.

* Add copy of daemon doc from Wiki
* Document the daemon.connected event

* Send an event at startup with the protocol version and pid

The pid will help with some of the issues of terminate the process when launched through a shell script and the version will allow clients to make decisions about supported features.

I've also bumped the protocol version number for two reasons:

1. This change
2. We didn't increase it when we added the previous emulator commands

https://github.com/flutter/flutter/issues/17956

* Add a `debugInstrumentAction()` method that will wrap an action
  in a stopwatch and print the time it took to run the action.
* Add a global `debugInstrumentationEnabled` that will control
  whether `debugInstrumentAction()` does anything (even in debug
  builds).
* Add some basic instrumentation to `registerServiceExtension()`
* Temporarily enable the `debugInstrumentationEnabled` flag in the
  Gallery to give us better visibility into what's happening in
  https://github.com/flutter/flutter/issues/17956

This reverts commit 0f557e72.

Enable --sync-async in Flutter.
Fixes #16801 

This reverts commit dac1baf4.

This is with dart roll.

This is one before dart roll.

When running with --local-engine, build single-architecture apps, rather
than what's declared in the Xcode project.

By default, Flutter creates Xcode projects that generate universal
binaries supporting both armv7 and arm64 processors. Since local engine builds
are all single-architecture, override the Xcode project's ARCHS setting
with the appropriate value for the specific engine.

NOTE: this assumes engine paths consistent with those used in the engine
repo: 32-bit iOS engine builds end in _arm, 64-bit builds do not.

* Fully rename to hot restart

Follow-up change to https://github.com/flutter/flutter/commit/f48dec570c899d8e222f5b3b7cbebd7d19fe6843

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