Investigate MPFlutterChart throws NOT_IMPLEMENTED

in flutter_flames_chart.dart a dashed line causes a NOT IMPLEMENTED exception for dash path. This fails in the BOTS doesn't fail locally (could it be a headless Flutter issue?). Enabling the below:

        // TODO(terry): Below crashed Flutter.
        // ..enableDashedLine(5, 5, 0)

Failure:

` 00:43 +119: /home/travis/build/flutter/devtools/packages/devtools_app/test/flutter/timeline_screen_test.dart: TimelineScreen builds proper content for timeline modes492══╡ EXCEPTION CAUGHT BY RENDERING LIBRARY ╞═════════════════════════════════════════════════════════

The following UnimplementedError was thrown during paint(): UnimplementedError495496The relevant error-causing widget was: CustomPaint org-dartlang-app:///packages/mp_chart/mp/chart/chart.dart:110:31498499When the exception was thrown, this was the stack:

package:dart-sdk/lib/_internal/js_dev_runtime/private/ddc_runtime/errors.dart 194:49 throw

package:build_web_compilers/lib/ui/src/ui/path_metrics.dart 72:24 get length package:path_drawing/src/dash_path.dart 29:51 dashPath package:mp_chart/mp/core/adapter_android_mp.dart 22:12 convert2DashPath package:mp_chart/mp/core/render/y_axis_renderer.dart 333:26 renderLimitLines package:mp_chart/mp/painter/bar_line_chart_painter.dart 296:49 onPaint package:mp_chart/mp/painter/painter.dart 242:5 paint package:flutter/src/rendering/custom_paint.dart 531:12 [_paintWithPainter] package:flutter/src/rendering/custom_paint.dart 572:7 paint package:flutter/src/rendering/object.dart 2219:7 [_paintWithContext] package:flutter/src/rendering/object.dart 184:12 paintChild package:flutter/src/rendering/proxy_box.dart 123:14 paint package:flutter/src/rendering/object.dart 2219:7 [_paintWithContext] package:flutter/src/rendering/object.dart 184:12 paintChild package:flutter/src/rendering/proxy_box.dart 123:14 paint package:flutter/src/rendering/object.dart 2219:7

...

_startMicrotaskLoop664package:dart-sdk/lib/_internal/js_dev_runtime/patch/async_patch.dart 166:15 665666The following RenderObject was being processed when the exception was fired: RenderCustomPaint#6cc2b NEEDS-PAINT DETACHED: creator: CustomPaint ← _PointerListener ← Listener ← _GestureSemantics ← RawGestureDetector ← GestureDetector ← ConstrainedBox ← Stack ← DecoratedBox ← Container ← RepaintBoundary-[GlobalKey#83f23] ← Screenshot ← ⋯ parentData: (can use size)671 constraints: BoxConstraints(w=1599.0, h=200.0) size: Size(1599.0, 200.0) This RenderObject has no descendants.`

flutter / devtools

Investigate MPFlutterChart throws NOT_IMPLEMENTED #1338