Convert PointerEvent's toString to Diagnosticable (#27904)

Rather than building a description string by hand, use Diagnosticable
properties. Simplifies output, since many fields have uninteresting
default values in many cases, and makes it easier to add more loggable
properties in subclasses.

Issue #28014

packages/flutter/lib/src/gestures/events.dart

@@ -90,7 +90,7 @@ int nthStylusButton(int number) => (kPrimaryStylusButton << (number - 1)) & kMax
 ///
 ///  * [Window.devicePixelRatio], which defines the device's current resolution.
 @immutable
-abstract class PointerEvent {
+abstract class PointerEvent extends Diagnosticable {
   /// Abstract const constructor. This constructor enables subclasses to provide
   /// const constructors so that they can be used in const expressions.
   const PointerEvent({
@@ -288,36 +288,37 @@ abstract class PointerEvent {
   final bool synthesized;
 
   @override
-  String toString() => '$runtimeType($position)';
+  void debugFillProperties(DiagnosticPropertiesBuilder properties) {
+    super.debugFillProperties(properties);
+    properties.add(DiagnosticsProperty<Offset>('position', position));
+    properties.add(DiagnosticsProperty<Offset>('delta', delta, defaultValue: Offset.zero, level: DiagnosticLevel.debug));
+    properties.add(DiagnosticsProperty<Duration>('timeStamp', timeStamp, defaultValue: Duration.zero, level: DiagnosticLevel.debug));
+    properties.add(IntProperty('pointer', pointer, level: DiagnosticLevel.debug));
+    properties.add(EnumProperty<PointerDeviceKind>('kind', kind, level: DiagnosticLevel.debug));
+    properties.add(IntProperty('device', device, defaultValue: 0, level: DiagnosticLevel.debug));
+    properties.add(IntProperty('buttons', buttons, defaultValue: 0, level: DiagnosticLevel.debug));
+    properties.add(DiagnosticsProperty<bool>('down', down, level: DiagnosticLevel.debug));
+    properties.add(DoubleProperty('pressure', pressure, defaultValue: 1.0, level: DiagnosticLevel.debug));
+    properties.add(DoubleProperty('pressureMin', pressureMin, defaultValue: 1.0, level: DiagnosticLevel.debug));
+    properties.add(DoubleProperty('pressureMax', pressureMax, defaultValue: 1.0, level: DiagnosticLevel.debug));
+    properties.add(DoubleProperty('distance', distance, defaultValue: 0.0, level: DiagnosticLevel.debug));
+    properties.add(DoubleProperty('distanceMin', distanceMin, defaultValue: 0.0, level: DiagnosticLevel.debug));
+    properties.add(DoubleProperty('distanceMax', distanceMax, defaultValue: 0.0, level: DiagnosticLevel.debug));
+    properties.add(DoubleProperty('size', size, defaultValue: 0.0, level: DiagnosticLevel.debug));
+    properties.add(DoubleProperty('radiusMajor', radiusMajor, defaultValue: 0.0, level: DiagnosticLevel.debug));
+    properties.add(DoubleProperty('radiusMinor', radiusMinor, defaultValue: 0.0, level: DiagnosticLevel.debug));
+    properties.add(DoubleProperty('radiusMin', radiusMin, defaultValue: 0.0, level: DiagnosticLevel.debug));
+    properties.add(DoubleProperty('radiusMax', radiusMax, defaultValue: 0.0, level: DiagnosticLevel.debug));
+    properties.add(DoubleProperty('orientation', orientation, defaultValue: 0.0, level: DiagnosticLevel.debug));
+    properties.add(DoubleProperty('tilt', tilt, defaultValue: 0.0, level: DiagnosticLevel.debug));
+    properties.add(IntProperty('platformData', platformData, defaultValue: 0, level: DiagnosticLevel.debug));
+    properties.add(FlagProperty('obscured', value: obscured, ifTrue: 'obscured', level: DiagnosticLevel.debug));
+    properties.add(FlagProperty('synthesized', value: synthesized, ifTrue: 'synthesized', level: DiagnosticLevel.debug));
+  }
 
   /// Returns a complete textual description of this event.
   String toStringFull() {
-    return '$runtimeType('
-             'timeStamp: $timeStamp, '
-             'pointer: $pointer, '
-             'kind: $kind, '
-             'device: $device, '
-             'position: $position, '
-             'delta: $delta, '
-             'buttons: $buttons, '
-             'down: $down, '
-             'obscured: $obscured, '
-             'pressure: $pressure, '
-             'pressureMin: $pressureMin, '
-             'pressureMax: $pressureMax, '
-             'distance: $distance, '
-             'distanceMin: $distanceMin, '
-             'distanceMax: $distanceMax, '
-             'size: $size, '
-             'radiusMajor: $radiusMajor, '
-             'radiusMinor: $radiusMinor, '
-             'radiusMin: $radiusMin, '
-             'radiusMax: $radiusMax, '
-             'orientation: $orientation, '
-             'tilt: $tilt, '
-             'platformData: $platformData, '
-             'synthesized: $synthesized'
-           ')';
+    return toString(minLevel: DiagnosticLevel.fine);
   }
 }