[layoutng] Add a shrink-to-fit flag to the constraint space

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

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "core/layout/ng/ng_length_utils.h"
 
 #include "core/layout/ng/ng_constraint_space.h"
 #include "core/layout/ng/ng_constraint_space_builder.h"
 #include "core/layout/ng/ng_fragment_base.h"
 #include "core/style/ComputedStyle.h"
 #include "platform/LayoutUnit.h"
 #include "platform/Length.h"
 #include "wtf/Optional.h"
 
 namespace blink {
 // TODO(layout-ng):
 // - positioned and/or replaced calculations
 // - Take scrollbars into account
 
-bool NeedMinAndMaxContentSizes(const ComputedStyle& style) {
-  // TODO(layout-ng): In the future we may pass a shrink-to-fit flag through the
-  // constraint space; if so, this function needs to take a constraint space
-  // as well to take that into account.
+bool NeedMinAndMaxContentSizes(const NGConstraintSpace& constraint_space,
+                               const ComputedStyle& style) {
   // This check is technically too broad (fill-available does not need intrinsic
   // size computation) but that's a rare case and only affects performance, not
   // correctness.
-  return style.logicalWidth().isIntrinsic() ||
+  return constraint_space.IsShrinkToFit() ||
+         style.logicalWidth().isIntrinsic() ||
          style.logicalMinWidth().isIntrinsic() ||
          style.logicalMaxWidth().isIntrinsic();
 }
 
 bool NeedMinAndMaxContentSizesForContentContribution(
     const ComputedStyle& style) {
-  return NeedMinAndMaxContentSizes(style) || style.logicalWidth().isAuto();
+  return style.logicalWidth().isIntrinsicOrAuto() ||
+         style.logicalMinWidth().isIntrinsic() ||
+         style.logicalMaxWidth().isIntrinsic();
 }
 
 LayoutUnit ResolveInlineLength(
     const NGConstraintSpace& constraint_space,
     const ComputedStyle& style,
     const WTF::Optional<MinAndMaxContentSizes>& min_and_max,
     const Length& length,
     LengthResolveType type) {
   // TODO(layout-ng): Handle min/max/fit-content
   DCHECK(!length.isMaxSizeNone());
@@ skipping 182 matching lines @@
   return computed_sizes;
 }
 
 LayoutUnit ComputeInlineSizeForFragment(
     const NGConstraintSpace& space,
     const ComputedStyle& style,
     const WTF::Optional<MinAndMaxContentSizes>& min_and_max) {
   if (space.IsFixedSizeInline())
     return space.AvailableSize().inline_size;
 
-  LayoutUnit extent =
-      ResolveInlineLength(space, style, min_and_max, style.logicalWidth(),
-                          LengthResolveType::kContentSize);
+  Length logicalWidth = style.logicalWidth();
+  if (logicalWidth.isAuto() && space.IsShrinkToFit())
+    logicalWidth = Length(FitContent);
+
+  LayoutUnit extent = ResolveInlineLength(
+      space, style, min_and_max, logicalWidth, LengthResolveType::kContentSize);
 
   Length max_length = style.logicalMaxWidth();
   if (!max_length.isMaxSizeNone()) {
     LayoutUnit max = ResolveInlineLength(space, style, min_and_max, max_length,
                                          LengthResolveType::kMaxSize);
     extent = std::min(extent, max);
   }
 
   LayoutUnit min =
       ResolveInlineLength(space, style, min_and_max, style.logicalMinWidth(),
@@ skipping 148 matching lines @@
     margins->inline_start = available_space / 2;
     margins->inline_end = available_space - margins->inline_start;
   } else if (style.marginStart().isAuto()) {
     margins->inline_start = available_space;
   } else if (style.marginEnd().isAuto()) {
     margins->inline_end = available_space;
   }
 }
 
 }  // namespace blink