[Perf/codesize] Reduce constraint member reads during layout (#51418)

packages/flutter/lib/src/cupertino/action_sheet.dart

@@ -668,6 +668,7 @@ class _RenderCupertinoAlert extends RenderBox {
 
   @override
   void performLayout() {
+    final BoxConstraints constraints = this.constraints;
     final bool hasDivider = contentSection.getMaxIntrinsicHeight(constraints.maxWidth) > 0.0
         && actionsSection.getMaxIntrinsicHeight(constraints.maxWidth) > 0.0;
     final double dividerThickness = hasDivider ? _dividerThickness : 0.0;

packages/flutter/lib/src/cupertino/dialog.dart

@@ -1540,6 +1540,7 @@ class _RenderCupertinoDialogActions extends RenderBox
 
   @override
   void performLayout() {
+    final BoxConstraints constraints = this.constraints;
     if (_isSingleButtonRow(dialogWidth)) {
       if (childCount == 1) {
         // We have 1 button. Our size is the width of the dialog and the height

packages/flutter/lib/src/cupertino/refresh.dart

@@ -104,6 +104,7 @@ class _RenderCupertinoSliverRefresh extends RenderSliver
 
   @override
   void performLayout() {
+    final SliverConstraints constraints = this.constraints;
     // Only pulling to refresh from the top is currently supported.
     assert(constraints.axisDirection == AxisDirection.down);
     assert(constraints.growthDirection == GrowthDirection.forward);

packages/flutter/lib/src/cupertino/segmented_control.dart

@@ -628,6 +628,7 @@ class _RenderSegmentedControl<T> extends RenderBox
 
   @override
   void performLayout() {
+    final BoxConstraints constraints = this.constraints;
     double maxHeight = _kMinSegmentedControlHeight;
 
     double childWidth = constraints.minWidth / childCount;

packages/flutter/lib/src/cupertino/sliding_segmented_control.dart

@@ -828,6 +828,7 @@ class _RenderSegmentedControl<T> extends RenderBox
 
   @override
   void performLayout() {
+    final BoxConstraints constraints = this.constraints;
     double childWidth = (constraints.minWidth - totalSeparatorWidth) / childCount;
     double maxHeight = _kMinSegmentedControlHeight;
 

packages/flutter/lib/src/cupertino/text_selection.dart

@@ -159,6 +159,7 @@ class _ToolbarRenderBox extends RenderShiftedBox {
 
   @override
   void performLayout() {
+    final BoxConstraints constraints = this.constraints;
     size = constraints.biggest;
 
     if (child == null) {

packages/flutter/lib/src/material/app_bar.dart

@@ -1346,6 +1346,7 @@ class _RenderAppBarTitleBox extends RenderAligningShiftedBox {
 
   @override
   void performLayout() {
+    final BoxConstraints constraints = this.constraints;
     final BoxConstraints innerConstraints = constraints.copyWith(maxHeight: double.infinity);
     child.layout(innerConstraints, parentUsesSize: true);
     size = constraints.constrain(child.size);

packages/flutter/lib/src/material/button.dart

@@ -509,6 +509,7 @@ class _RenderInputPadding extends RenderShiftedBox {
 
   @override
   void performLayout() {
+    final BoxConstraints constraints = this.constraints;
     if (child != null) {
       child.layout(constraints, parentUsesSize: true);
       final double height = math.max(child.size.width, minSize.width);

packages/flutter/lib/src/material/floating_action_button.dart

@@ -582,6 +582,7 @@ class _RenderChildOverflowBox extends RenderAligningShiftedBox {
 
   @override
   void performLayout() {
+    final BoxConstraints constraints = this.constraints;
     if (child != null) {
       child.layout(const BoxConstraints(), parentUsesSize: true);
       size = Size(

packages/flutter/lib/src/material/input_decorator.dart

@@ -1247,6 +1247,7 @@ class _RenderDecoration extends RenderBox {
 
   @override
   void performLayout() {
+    final BoxConstraints constraints = this.constraints;
     _labelTransform = null;
     final _RenderDecorationLayout layout = _layout(constraints);
 

packages/flutter/lib/src/material/list_tile.dart

@@ -1328,6 +1328,7 @@ class _RenderListTile extends RenderBox {
   // https://material.io/design/components/lists.html#specs
   @override
   void performLayout() {
+    final BoxConstraints constraints = this.constraints;
     final bool hasLeading = leading != null;
     final bool hasSubtitle = subtitle != null;
     final bool hasTrailing = trailing != null;

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

@@ -170,7 +170,7 @@ class RenderAnimatedSize extends RenderAligningShiftedBox {
   void performLayout() {
     _lastValue = _controller.value;
     _hasVisualOverflow = false;
-
+    final BoxConstraints constraints = this.constraints;
     if (child == null || constraints.isTight) {
       _controller.stop();
       size = _sizeTween.begin = _sizeTween.end = constraints.smallest;

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

@@ -1743,6 +1743,7 @@ class RenderEditable extends RenderBox with RelayoutWhenSystemFontsChangeMixin {
   }
   @override
   void performLayout() {
+    final BoxConstraints constraints = this.constraints;
     _layoutText(minWidth: constraints.minWidth, maxWidth: constraints.maxWidth);
     _caretPrototype = _getCaretPrototype;
     _selectionRects = null;

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

@@ -636,6 +636,8 @@ class RenderFlex extends RenderBox with ContainerRenderObjectMixin<RenderBox, Fl
   @override
   void performLayout() {
     assert(_debugHasNecessaryDirections);
+    final BoxConstraints constraints = this.constraints;
+
     // Determine used flex factor, size inflexible items, calculate free space.
     int totalFlex = 0;
     int totalChildren = 0;

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

@@ -279,6 +279,7 @@ class RenderFlow extends RenderBox
 
   @override
   void performLayout() {
+    final BoxConstraints constraints = this.constraints;
     size = _getSize(constraints);
     int i = 0;
     _randomAccessChildren.clear();

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

@@ -63,6 +63,7 @@ class RenderListBody extends RenderBox
 
   @override
   void performLayout() {
+    final BoxConstraints constraints = this.constraints;
     assert(() {
       switch (mainAxis) {
         case Axis.horizontal:

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

@@ -575,6 +575,7 @@ class RenderParagraph extends RenderBox
 
   @override
   void performLayout() {
+    final BoxConstraints constraints = this.constraints;
     _layoutChildren(constraints);
     _layoutTextWithConstraints(constraints);
     _setParentData();

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

@@ -260,6 +260,7 @@ class RenderConstrainedBox extends RenderProxyBox {
 
   @override
   void performLayout() {
+    final BoxConstraints constraints = this.constraints;
     if (child != null) {
       child.layout(_additionalConstraints.enforce(constraints), parentUsesSize: true);
       size = child.size;
@@ -351,6 +352,7 @@ class RenderLimitedBox extends RenderProxyBox {
   @override
   void performLayout() {
     if (child != null) {
+      final BoxConstraints constraints = this.constraints;
       child.layout(_limitConstraints(constraints), parentUsesSize: true);
       size = constraints.constrain(child.size);
     } else {

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

@@ -193,6 +193,7 @@ class RenderPadding extends RenderShiftedBox {
 
   @override
   void performLayout() {
+    final BoxConstraints constraints = this.constraints;
     _resolve();
     assert(_resolvedPadding != null);
     if (child == null) {
@@ -385,6 +386,7 @@ class RenderPositionedBox extends RenderAligningShiftedBox {
 
   @override
   void performLayout() {
+    final BoxConstraints constraints = this.constraints;
     final bool shrinkWrapWidth = _widthFactor != null || constraints.maxWidth == double.infinity;
     final bool shrinkWrapHeight = _heightFactor != null || constraints.maxHeight == double.infinity;
 
@@ -649,6 +651,7 @@ class RenderUnconstrainedBox extends RenderAligningShiftedBox with DebugOverflow
 
   @override
   void performLayout() {
+    final BoxConstraints constraints = this.constraints;
     if (child != null) {
       // Let the child lay itself out at it's "natural" size, but if
       // constrainedAxis is non-null, keep any constraints on that axis.
@@ -1183,6 +1186,7 @@ class RenderBaseline extends RenderShiftedBox {
   @override
   void performLayout() {
     if (child != null) {
+      final BoxConstraints constraints = this.constraints;
       child.layout(constraints.loosen(), parentUsesSize: true);
       final double childBaseline = child.getDistanceToBaseline(baselineType);
       final double actualBaseline = baseline;

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

@@ -1813,6 +1813,7 @@ class RenderSliverToBoxAdapter extends RenderSliverSingleBoxAdapter {
       geometry = SliverGeometry.zero;
       return;
     }
+    final SliverConstraints constraints = this.constraints;
     child.layout(constraints.asBoxConstraints(), parentUsesSize: true);
     double childExtent;
     switch (constraints.axis) {

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

@@ -87,6 +87,7 @@ class RenderSliverFillRemainingWithScrollable extends RenderSliverSingleBoxAdapt
 
   @override
   void performLayout() {
+    final SliverConstraints constraints = this.constraints;
     // TODO(Piinks): This may fill too much space for NestedScrollView, https://github.com/flutter/flutter/issues/46028
     final double extent = constraints.remainingPaintExtent - math.min(constraints.overlap, 0.0);
 
@@ -137,6 +138,7 @@ class RenderSliverFillRemaining extends RenderSliverSingleBoxAdapter {
 
   @override
   void performLayout() {
+    final SliverConstraints constraints = this.constraints;
     // The remaining space in the viewportMainAxisExtent. Can be <= 0 if we have
     // scrolled beyond the extent of the screen.
     double extent = constraints.viewportMainAxisExtent - constraints.precedingScrollExtent;
@@ -209,6 +211,7 @@ class RenderSliverFillRemainingAndOverscroll extends RenderSliverSingleBoxAdapte
 
   @override
   void performLayout() {
+    final SliverConstraints constraints = this.constraints;
     // The remaining space in the viewportMainAxisExtent. Can be <= 0 if we have
     // scrolled beyond the extent of the screen.
     double extent = constraints.viewportMainAxisExtent - constraints.precedingScrollExtent;

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

@@ -164,6 +164,7 @@ abstract class RenderSliverFixedExtentBoxAdaptor extends RenderSliverMultiBoxAda
 
   @override
   void performLayout() {
+    final SliverConstraints constraints = this.constraints;
     childManager.didStartLayout();
     childManager.setDidUnderflow(false);
 

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

@@ -511,6 +511,7 @@ class RenderSliverGrid extends RenderSliverMultiBoxAdaptor {
 
   @override
   void performLayout() {
+    final SliverConstraints constraints = this.constraints;
     childManager.didStartLayout();
     childManager.setDidUnderflow(false);
 

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

@@ -44,6 +44,7 @@ class RenderSliverList extends RenderSliverMultiBoxAdaptor {
 
   @override
   void performLayout() {
+    final SliverConstraints constraints = this.constraints;
     childManager.didStartLayout();
     childManager.setDidUnderflow(false);
 

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

@@ -118,6 +118,7 @@ abstract class RenderSliverEdgeInsetsPadding extends RenderSliver with RenderObj
 
   @override
   void performLayout() {
+    final SliverConstraints constraints = this.constraints;
     assert(resolvedPadding != null);
     final double beforePadding = this.beforePadding;
     final double afterPadding = this.afterPadding;

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

@@ -331,6 +331,7 @@ abstract class RenderSliverScrollingPersistentHeader extends RenderSliverPersist
 
   @override
   void performLayout() {
+    final SliverConstraints constraints = this.constraints;
     final double maxExtent = this.maxExtent;
     layoutChild(constraints.scrollOffset, maxExtent);
     final double paintExtent = maxExtent - constraints.scrollOffset;
@@ -369,6 +370,7 @@ abstract class RenderSliverPinnedPersistentHeader extends RenderSliverPersistent
 
   @override
   void performLayout() {
+    final SliverConstraints constraints = this.constraints;
     final double maxExtent = this.maxExtent;
     final bool overlapsContent = constraints.overlap > 0.0;
     excludeFromSemanticsScrolling = overlapsContent || (constraints.scrollOffset > maxExtent - minExtent);
@@ -552,6 +554,7 @@ abstract class RenderSliverFloatingPersistentHeader extends RenderSliverPersiste
 
   @override
   void performLayout() {
+    final SliverConstraints constraints = this.constraints;
     final double maxExtent = this.maxExtent;
     if (_lastActualScrollOffset != null && // We've laid out at least once to get an initial position, and either
         ((constraints.scrollOffset < _lastActualScrollOffset) || // we are scrolling back, so should reveal, or

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

@@ -517,6 +517,7 @@ class RenderStack extends RenderBox
 
   @override
   void performLayout() {
+    final BoxConstraints constraints = this.constraints;
     _resolve();
     assert(_resolvedAlignment != null);
     _hasVisualOverflow = false;

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

@@ -992,6 +992,7 @@ class RenderTable extends RenderBox {
 
   @override
   void performLayout() {
+    final BoxConstraints constraints = this.constraints;
     final int rows = this.rows;
     final int columns = this.columns;
     assert(_children.length == rows * columns);

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

@@ -1699,6 +1699,7 @@ class RenderShrinkWrappingViewport extends RenderViewportBase<SliverLogicalConta
 
   @override
   void performLayout() {
+    final BoxConstraints constraints = this.constraints;
     if (firstChild == null) {
       switch (axis) {
         case Axis.vertical:

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

@@ -565,6 +565,7 @@ class RenderWrap extends RenderBox with ContainerRenderObjectMixin<RenderBox, Wr
 
   @override
   void performLayout() {
+    final BoxConstraints constraints = this.constraints;
     assert(_debugHasNecessaryDirections);
     _hasVisualOverflow = false;
     RenderBox child = firstChild;

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

@@ -238,6 +238,7 @@ class _RenderLayoutBuilder extends RenderBox with RenderObjectWithChildMixin<Ren
 
   @override
   void performLayout() {
+    final BoxConstraints constraints = this.constraints;
     layoutAndBuildChild();
     if (child != null) {
       child.layout(constraints, parentUsesSize: true);

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

@@ -505,6 +505,7 @@ class _RenderSingleChildViewport extends RenderBox with RenderObjectWithChildMix
 
   @override
   void performLayout() {
+    final BoxConstraints constraints = this.constraints;
     if (child == null) {
       size = constraints.smallest;
     } else {