* migrate widget to nullsafety
* remove double blank line after license
* address review comments in actions.dart
* nullable ObjectKey.value
* use local variable oldElement
* make State.build non-nullable
* make State.context non-nullable
* newline at eof
* make ProxyWidget.child non-nullable
* make _InactiveElements.debugContains non-nullable
* make Element.depth non-nullable
* make ProxyElement.build non-nullable
* make StatefulElement.state non-nullable
* remove 'Notice that'
* avoid cast of list in RenderObjectElement.updateChildren
* make IndexedSlot.value non-nullable
* avoid cast of list in MultiChildRenderObjectElement.mount
* make some WidgetsApp parameters non-nullable
* hitTest take non-nullable position
* make ScrollableState.position non-nullable
* use _pixels instead of pixels
* make ViewportOffset.pixels non-nullable
* make param and return type of IndexedWidgetBuilder non-nullable
* unused_import
* make context param non-nullable for Builder in animated_list.dart
* make ScrollMetrics.viewportDimension non-nullable
* make ScrollMetrics.{min,max}ScrollExtent non-nullable
* make _Location.file non-nullable
* _WidgetForTypeTests.createElement throw UnimplementedError
* update _NullWidget.build error message
* make _ShortcutsState.manager non-nullable
* Fix childCount issues for NNBD
* fix childCount computation on web
* increase max value on js side to compute childCount
* make aspect parameter of dependOnInheritedWidgetOfExactType nullable
* merge has{min,max}ScrollExtent into hasScrollExtents
* update focus_manager.dart
* address review comments in icon.dart
* address review comments in image.dart
* address review comments in routes.dart
* address review comments in scroll_activity.dart
* update doc comments
* make UserScrollNotification.direction non-nullable and required
* rename hasScrollExtents to hasContentDimensions
* unnecessary late
Co-authored-by: Ian Hickson <ian@hixie.ch>
This allows us to rationalize the nullability of some of our APIs.
Prior to this we'd end up in a situation where Container assumed that
getClipPath would be non-null but Decoration was ok with return null.
Previous benchmarks have established the performance of sync*. Additionally, why allocate a list when you don't need to? Since these APIs are private, they can be re-arranged a bit to avoid creating as many lists. Will probably not have a large effect on benchmarks
* Redesigns the interface between MouseTracker and RendererBinding&RenderView.
* Simplifies the structure of RenderMouseRegion.
* Extracts the common utility code between mouse_tracker_test and mouse_tracker_cursor_test.
After #31935, Some one sequence gesture recognizers requires at least one callback to be able to compete in the arena. This PR adds the a no-op callback in the gesture recognizer in the platform view when the gesture recognizer does not have any callbacks. This way, all the gesture recognizers in the platform view can compete in the arena.
