[AspectRatio] Correctly compute flex line length

Because flexbox passes in LayoutUnit::Max(), ng_length_utils used
that as the minimum block size, so effectively we ignored the
aspect ratio.

The test was incorrect. See also https://github.com/w3c/csswg-drafts/issues/5406

R=ikilpatrick@chromium.org, mstensho@chromium.org

Bug: 1083010, 1045668
Change-Id: I2ed30cb6d9539ea82ac5c22b34c45770fa9a60a8
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2479802
Auto-Submit: Christian Biesinger <cbiesinger@chromium.org>
Reviewed-by: Ian Kilpatrick <ikilpatrick@chromium.org>
Commit-Queue: Christian Biesinger <cbiesinger@chromium.org>
Cr-Commit-Position: refs/heads/master@{#818452}

third_party/blink/renderer/core/layout/layout_box.cc

@@ -1300,6 +1300,7 @@ LayoutUnit LayoutBox::ConstrainLogicalHeightByMinMax(
   if (logical_min_height.IsAuto() &&
       ShouldComputeLogicalHeightFromAspectRatio() &&
       intrinsic_content_height != kIndefiniteSize &&
+      intrinsic_content_height != LayoutUnit::Max() &&
       StyleRef().OverflowBlockDirection() == EOverflow::kVisible) {
     logical_min_height = Length::Fixed(intrinsic_content_height);
   }

third_party/blink/renderer/core/layout/ng/ng_length_utils.cc

@@ -594,10 +594,15 @@ LayoutUnit ComputeBlockSizeForFragmentInternal(
                                  style.BoxSizing(), *inline_size);
     // Apply the automatic minimum size for aspect ratio:
     // https://drafts.csswg.org/css-sizing-4/#aspect-ratio-minimum
+    // We also check for LayoutUnit::Max() because flexbox uses that as a
+    // "placeholder" to compute the flex line length while still respecting
+    // max-block-size.
     if (style.LogicalMinHeight().IsAuto() &&
         style.OverflowBlockDirection() == EOverflow::kVisible &&
-        intrinsic_size != kIndefiniteSize)
+        intrinsic_size != kIndefiniteSize &&
+        intrinsic_size != LayoutUnit::Max()) {
       min_max.min_size = intrinsic_size;
+    }
   } else if (extent == kIndefiniteSize) {
     DCHECK_EQ(intrinsic_size, kIndefiniteSize);
     return extent;

third_party/blink/web_tests/external/wpt/css/css-sizing/aspect-ratio/flex-aspect-ratio-008.tentative.html

@@ -7,7 +7,7 @@
 
 <p>Test passes if there is a filled green square and <strong>no red</strong>.</p>
 
-<div style="display: flex; flex-direction: column; flex-wrap: wrap; width: 200px; aspect-ratio: 4/1;">
-  <div style="background: green; width: 100px; height: 50px;"></div>
-  <div style="background: green; width: 100px; height: 50px;"></div>
+<div style="display: flex; flex-direction: column; flex-wrap: wrap; width: 100px; aspect-ratio: 1/1;">
+  <div style="background: green; width: 50px; height: 100px;"></div>
+  <div style="background: green; width: 50px; height: 100px;"></div>
 </div>