Revert "Expose LineMetrics in TextPainter through `computeLineMetrics`. (#39282)" (#39504)

This reverts commit d67f47b21e49530a07df38a9108edac854b6b286.

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

diff --git a/packages/flutter/lib/src/painting/text_painter.dart b/packages/flutter/lib/src/painting/text_painter.dart
index 8b31be3..227cd76 100644
--- a/packages/flutter/lib/src/painting/text_painter.dart
+++ b/packages/flutter/lib/src/painting/text_painter.dart
@@ -3,7 +3,7 @@
 // found in the LICENSE file.
 
 import 'dart:math' show min, max;
-import 'dart:ui' as ui show Paragraph, ParagraphBuilder, ParagraphConstraints, ParagraphStyle, PlaceholderAlignment, LineMetrics;
+import 'dart:ui' as ui show Paragraph, ParagraphBuilder, ParagraphConstraints, ParagraphStyle, PlaceholderAlignment;
 
 import 'package:flutter/foundation.dart';
 import 'package:flutter/gestures.dart';
@@ -816,24 +816,4 @@
     final List<int> indices = _paragraph.getWordBoundary(position.offset);
     return TextRange(start: indices[0], end: indices[1]);
   }
-
-  /// Returns the full list of [LineMetrics] that describe in detail the various
-  /// metrics of each laid out line.
-  ///
-  /// The [LineMetrics] list is presented in the order of the lines they represent.
-  /// For example, the first line is in the zeroth index.
-  ///
-  /// [LineMetrics] contains measurements such as ascent, descent, baseline, and
-  /// width for the line as a whole, and may be useful for aligning additional
-  /// widgets to a particular line.
-  ///
-  /// Valid only after [layout] has been called.
-  ///
-  /// This can potentially return a large amount of data, so it is not recommended
-  /// to repeatedly call this. Instead, cache the results. The cached results
-  /// should be invalidated upon the next sucessful [layout].
-  List<ui.LineMetrics> computeLineMetrics() {
-    assert(!_needsLayout);
-    return _paragraph.computeLineMetrics();
-  }
 }

packages/flutter/test/painting/text_painter_test.dart

diff --git a/packages/flutter/test/painting/text_painter_test.dart b/packages/flutter/test/painting/text_painter_test.dart
index 72eafda..1c354f6 100644
--- a/packages/flutter/test/painting/text_painter_test.dart
+++ b/packages/flutter/test/painting/text_painter_test.dart
@@ -729,65 +729,4 @@
     expect(painter.inlinePlaceholderBoxes[12], const TextBox.fromLTRBD(300, 30, 351, 60, TextDirection.ltr));
     expect(painter.inlinePlaceholderBoxes[13], const TextBox.fromLTRBD(351, 30, 401, 60, TextDirection.ltr));
   }, skip: isBrowser);
-
-  test('TextPainter line metrics', () {
-    final TextPainter painter = TextPainter()
-      ..textDirection = TextDirection.ltr;
-
-    const String text = 'test1\nhello line two really long for soft break\nfinal line 4';
-    painter.text = const TextSpan(
-      text: text,
-    );
-
-    painter.layout(maxWidth: 300);
-
-    final List<ui.LineMetrics> lines = painter.computeLineMetrics();
-
-    expect(lines.length, 4);
-
-    expect(lines[0].hardBreak, true);
-    expect(lines[1].hardBreak, false);
-    expect(lines[2].hardBreak, true);
-    expect(lines[3].hardBreak, true);
-
-    expect(lines[0].ascent, 11.199999809265137);
-    expect(lines[1].ascent, 11.199999809265137);
-    expect(lines[2].ascent, 11.199999809265137);
-    expect(lines[3].ascent, 11.199999809265137);
-
-    expect(lines[0].descent, 2.799999952316284);
-    expect(lines[1].descent, 2.799999952316284);
-    expect(lines[2].descent, 2.799999952316284);
-    expect(lines[3].descent, 2.799999952316284);
-
-    expect(lines[0].unscaledAscent, 11.199999809265137);
-    expect(lines[1].unscaledAscent, 11.199999809265137);
-    expect(lines[2].unscaledAscent, 11.199999809265137);
-    expect(lines[3].unscaledAscent, 11.199999809265137);
-
-    expect(lines[0].baseline, 11.200000047683716);
-    expect(lines[1].baseline, 25.200000047683716);
-    expect(lines[2].baseline, 39.200000047683716);
-    expect(lines[3].baseline, 53.200000047683716);
-
-    expect(lines[0].height, 14);
-    expect(lines[1].height, 14);
-    expect(lines[2].height, 14);
-    expect(lines[3].height, 14);
-
-    expect(lines[0].width, 70);
-    expect(lines[1].width, 294);
-    expect(lines[2].width, 266);
-    expect(lines[3].width, 168);
-
-    expect(lines[0].left, 0);
-    expect(lines[1].left, 0);
-    expect(lines[2].left, 0);
-    expect(lines[3].left, 0);
-
-    expect(lines[0].lineNumber, 0);
-    expect(lines[1].lineNumber, 1);
-    expect(lines[2].lineNumber, 2);
-    expect(lines[3].lineNumber, 3);
-  }, skip: isBrowser);
 }