[layoutng] Add a function to compute the min- and max-content contribution

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

 // 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.
 
 #ifndef NGLengthUtils_h
 #define NGLengthUtils_h
 
 #include "core/CoreExport.h"
 #include "core/layout/ng/ng_units.h"
 #include "core/layout/ng/ng_writing_mode.h"
@@ skipping 17 matching lines @@
 };
 
 #define NGSizeIndefinite LayoutUnit(-1)
 
 // Whether the caller needs to compute min-content and max-content sizes to
 // pass them to ResolveInlineLength / ComputeInlineSizeForFragment.
 // If this function returns false, it is safe to pass an empty
 // MinAndMaxContentSizes struct to those functions.
 CORE_EXPORT bool NeedMinAndMaxContentSizes(const ComputedStyle&);
 
+// Like NeedMinAndMaxContentSizes, but for use when calling
+// ComputeMinAndMaxContentContribution.
+CORE_EXPORT bool NeedMinAndMaxContentSizesForContentContribution(
+    const ComputedStyle&);
+
 // Convert an inline-axis length to a layout unit using the given constraint
 // space.
 CORE_EXPORT LayoutUnit
 ResolveInlineLength(const NGConstraintSpace&,
                     const ComputedStyle&,
                     const WTF::Optional<MinAndMaxContentSizes>&,
                     const Length&,
                     LengthResolveType);
 
 // Convert a block-axis length to a layout unit using the given constraint
 // space and content size.
 CORE_EXPORT LayoutUnit ResolveBlockLength(const NGConstraintSpace&,
                                           const ComputedStyle&,
                                           const Length&,
                                           LayoutUnit content_size,
                                           LengthResolveType);
 
+// For the given style and min/max content sizes, computes the min and max
+// content contribution (https://drafts.csswg.org/css-sizing/#contributions).
+// This is similar to ComputeInlineSizeForFragment except that it does not
+// require a constraint space (percentage sizes as well as auto margins compute
+// to zero) and that an auto inline size resolves to the respective min/max
+// content size.
+// Also, the min/max contribution does include the inline margins as well.
+CORE_EXPORT MinAndMaxContentSizes ComputeMinAndMaxContentContribution(
+    const ComputedStyle&,
+    const WTF::Optional<MinAndMaxContentSizes>&);
+
 // Resolves the given length to a layout unit, constraining it by the min
 // logical width and max logical width properties from the ComputedStyle
 // object.
 CORE_EXPORT LayoutUnit
 ComputeInlineSizeForFragment(const NGConstraintSpace&,
                              const ComputedStyle&,
                              const WTF::Optional<MinAndMaxContentSizes>&);
 
 // Resolves the given length to a layout unit, constraining it by the min
 // logical height and max logical height properties from the ComputedStyle
@@ skipping 35 matching lines @@
 // the fragment to compute the margins that are auto, if any, and adjusts
 // the given NGBoxStrut accordingly.
 CORE_EXPORT void ApplyAutoMargins(const NGConstraintSpace&,
                                   const ComputedStyle&,
                                   const NGFragmentBase&,
                                   NGBoxStrut* margins);
 
 }  // namespace blink
 
 #endif  // NGLengthUtils_h