[layoutng] Correctly resolve indefinite percentages

third_party/WebKit/Source/core/layout/ng/ng_length_utils.cc

Index: third_party/WebKit/Source/core/layout/ng/ng_length_utils.cc
diff --git a/third_party/WebKit/Source/core/layout/ng/ng_length_utils.cc b/third_party/WebKit/Source/core/layout/ng/ng_length_utils.cc
index 53713be8297314022d3c48a35bd918882ad225a7..454d1ea14e4ce8d97ba325e5bdb1a36e42b19ba2 100644
--- a/third_party/WebKit/Source/core/layout/ng/ng_length_utils.cc
+++ b/third_party/WebKit/Source/core/layout/ng/ng_length_utils.cc
@@ -21,6 +21,7 @@ LayoutUnit resolveInlineLength(const NGConstraintSpace& constraintSpace,
                                LengthResolveType type) {
   // TODO(layout-ng): Handle min/max/fit-content
   DCHECK(!length.isMaxSizeNone());
+  DCHECK_GE(constraintSpace.ContainerSize().inlineSize, LayoutUnit());
 
   if (type == LengthResolveType::MinSize && length.isAuto())
     return LayoutUnit();
@@ -47,6 +48,12 @@ LayoutUnit resolveBlockLength(const NGConstraintSpace& constraintSpace,
   if (length.isMinContent() || length.isMaxContent() || length.isFitContent())
     return contentSize;
 
+  // Make sure that indefinite percentages resolve to NGSizeIndefinite, not to
+  // a random negative number.
+  if (length.hasPercent() &&
+      constraintSpace.ContainerSize().blockSize == NGSizeIndefinite)
+    return contentSize;
+
   return valueForLength(length, constraintSpace.ContainerSize().blockSize);
 }
 
@@ -86,8 +93,12 @@ LayoutUnit computeBlockSizeForFragment(const NGConstraintSpace& constraintSpace,
   LayoutUnit extent =
       resolveBlockLength(constraintSpace, style.logicalHeight(), contentSize,
                          LengthResolveType::ContentSize);
-  Length maxLength = style.logicalMaxHeight();
+  if (extent == NGSizeIndefinite) {
+    DCHECK_EQ(contentSize, NGSizeIndefinite);
+    return extent;
+  }
 
+  Length maxLength = style.logicalMaxHeight();
   if (!maxLength.isMaxSizeNone()) {
     LayoutUnit max = resolveBlockLength(constraintSpace, maxLength, contentSize,
                                         LengthResolveType::MaxSize);