Remove more rounding hacks from TextPainter (#127826)

Add the conditional rounding that I forgot to add in https://github.com/flutter/flutter/pull/127099

packages/flutter/lib/src/painting/text_painter.dart

@@ -362,8 +362,10 @@ class _TextPainterLayoutCacheWithOffset {
   static double _contentWidthFor(double minWidth, double maxWidth, TextWidthBasis widthBasis, _TextLayout layout) {
     // TODO(LongCatIsLooong): remove the rounding when _applyFloatingPointHack
     // is removed.
-    minWidth = minWidth.floorToDouble();
-    maxWidth = maxWidth.floorToDouble();
+    if (_TextLayout._shouldApplyFloatingPointHack) {
+      minWidth = minWidth.floorToDouble();
+      maxWidth = maxWidth.floorToDouble();
+    }
     return switch (widthBasis) {
       TextWidthBasis.longestLine => clampDouble(layout.longestLine, minWidth, maxWidth),
       TextWidthBasis.parent => clampDouble(layout.maxIntrinsicLineExtent, minWidth, maxWidth),

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

@@ -5041,14 +5041,8 @@ class _ScribbleFocusableState extends State<_ScribbleFocusable> implements Scrib
 class _ScribblePlaceholder extends WidgetSpan {
   const _ScribblePlaceholder({
     required super.child,
-    super.alignment,
-    super.baseline,
     required this.size,
-  }) : assert(baseline != null || !(
-         identical(alignment, ui.PlaceholderAlignment.aboveBaseline) ||
-         identical(alignment, ui.PlaceholderAlignment.belowBaseline) ||
-         identical(alignment, ui.PlaceholderAlignment.baseline)
-       ));
+  });
 
   /// The size of the span, used in place of adding a placeholder size to the [TextPainter].
   final Size size;

packages/flutter/test/material/date_range_picker_test.dart

@@ -132,7 +132,10 @@ void main() {
       final Offset entryButtonBottomLeft = tester.getBottomLeft(
         find.widgetWithIcon(IconButton, Icons.edit_outlined),
       );
-      expect(saveButtonBottomLeft.dx, 800 - 89.0);
+      expect(
+        saveButtonBottomLeft.dx,
+        const bool.hasEnvironment('SKPARAGRAPH_REMOVE_ROUNDING_HACK') ? moreOrLessEquals(711.6, epsilon: 1e-5) : (800 - 89.0),
+      );
       expect(saveButtonBottomLeft.dy, helpTextTopLeft.dy);
       expect(entryButtonBottomLeft.dx, saveButtonBottomLeft.dx - 48.0);
       expect(entryButtonBottomLeft.dy, helpTextTopLeft.dy);