Revert "Sliver Constrained Cross Axis" (flutter#125233)

Going to make some changes to the implementation so I'll revert in the meantime.

Reverts flutter#124337

packages/flutter/lib/src/rendering/proxy_sliver.dart

@@ -2,7 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-import 'dart:math';
 import 'dart:ui' as ui show Color;
 
 import 'package:flutter/animation.dart';
@@ -415,42 +414,3 @@ class RenderSliverAnimatedOpacity extends RenderProxySliver with RenderAnimatedO
     child = sliver;
   }
 }
-
-/// Applies a cross-axis constraint to its sliver child.
-///
-/// This render object takes a [maxExtent] parameter and uses the smaller of
-/// [maxExtent] and the parent's [SliverConstraints.crossAxisExtent] as the
-/// cross axis extent of the [SliverConstraints] passed to the sliver child.
-class RenderSliverConstrainedCrossAxis extends RenderProxySliver {
-  /// Creates a render object that constrains the cross axis extent of its sliver child.
-  ///
-  /// The [maxExtent] parameter must not be null and must be nonnegative.
-  RenderSliverConstrainedCrossAxis({
-    required double maxExtent
-  }) : _maxExtent = maxExtent,
-       assert(maxExtent >= 0.0);
-
-  /// The cross axis extent to apply to the sliver child.
-  ///
-  /// This value must be nonnegative.
-  double get maxExtent => _maxExtent;
-  double _maxExtent;
-  set maxExtent(double value) {
-    if (_maxExtent == value) {
-      return;
-    }
-    _maxExtent = value;
-    markNeedsLayout();
-  }
-
-  @override
-  void performLayout() {
-    assert(child != null);
-    assert(maxExtent >= 0.0);
-    child!.layout(
-      constraints.copyWith(crossAxisExtent: min(_maxExtent, constraints.crossAxisExtent)),
-      parentUsesSize: true,
-    );
-    geometry = child!.geometry;
-  }
-}

packages/flutter/lib/src/widgets/sliver.dart

@@ -1365,47 +1365,3 @@ class KeepAlive extends ParentDataWidget<KeepAliveParentDataMixin> {
     properties.add(DiagnosticsProperty<bool>('keepAlive', keepAlive));
   }
 }
-
-/// A sliver that constrains the cross axis extent of its sliver child.
-///
-/// The [SliverConstrainedCrossAxis] takes a [maxExtent] parameter and uses it as
-/// the cross axis extent of the [SliverConstraints] passed to the sliver child.
-/// The widget ensures that the [maxExtent] is a nonnegative value.
-///
-/// This is useful when you want to apply a custom cross-axis extent constraint
-/// to a sliver child, as slivers typically consume the full cross axis extent.
-///
-/// {@tool dartpad}
-/// In this sample the [SliverConstrainedCrossAxis] sizes its [child] so that the
-/// cross axis extent takes up less space than the actual viewport.
-///
-/// ** See code in examples/api/lib/widgets/sliver/sliver_constrained_cross_axis.0.dart **
-/// {@end-tool}
-
-class SliverConstrainedCrossAxis extends SingleChildRenderObjectWidget {
-  /// Creates a sliver that constrains the cross axis extent of its sliver child.
-  ///
-  /// The [maxExtent] parameter is required and must be nonnegative.
-  const SliverConstrainedCrossAxis({
-    super.key,
-    required this.maxExtent,
-    required Widget sliver,
-  }) : assert(maxExtent >= 0.0),
-       super(child: sliver);
-
-  /// The cross axis extent to apply to the sliver child.
-  ///
-  /// This value must be nonnegative.
-  final double maxExtent;
-
-  @override
-  RenderSliverConstrainedCrossAxis createRenderObject(BuildContext context) {
-    return RenderSliverConstrainedCrossAxis(maxExtent: maxExtent);
-  }
-
-  @override
-  void updateRenderObject(
-      BuildContext context, RenderSliverConstrainedCrossAxis renderObject) {
-    renderObject.maxExtent = maxExtent;
-  }
-}