[LayoutNG] Fix DCHECK in NGLineBreaker::ComputeLineLocation

Bug: 999075
Test: fast/text/nowrap-with-saturated-padding.html
Change-Id: Ie8aa9c98ab9cf2f868d24472a2362f54cad19273
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1775217
Auto-Submit: Emil A Eklund <eae@chromium.org>
Commit-Queue: Koji Ishii <kojii@chromium.org>
Reviewed-by: Koji Ishii <kojii@chromium.org>
Cr-Commit-Position: refs/heads/master@{#691935}

third_party/blink/renderer/core/layout/ng/inline/ng_line_breaker.cc

@@ -471,7 +471,10 @@ void NGLineBreaker::ComputeLineLocation(NGLineInfo* line_info) const {
   // Negative margins can make the position negative, but the inline size is
   // always positive or 0.
   LayoutUnit available_width = AvailableWidth();
-  DCHECK_EQ(position_, line_info->ComputeWidth());
+
+  // Text measurement is done using floats which may introduce small rounding
+  // errors for near-saturated values.
+  DCHECK_EQ(position_.Round(), line_info->ComputeWidth().Round());
 
   line_info->SetWidth(available_width, position_);
   line_info->SetBfcOffset(

third_party/blink/web_tests/fast/text/nowrap-with-saturated-padding-expected.txt

+ Should not crash

third_party/blink/web_tests/fast/text/nowrap-with-saturated-padding.html

+<style>
+label { white-space: nowrap;  }
+meter { padding-right: 99999999px; }
+</style>
+<script>
+if (window.testRunner)
+  testRunner.dumpAsText();
+</script>
+<label>
+<meter></meter>
+</label>
+Should not crash
\ No newline at end of file