LibWeb: Express intrinsic size layout via size constraints

Previously, we had three layout modes:

- Normal:
    - Everything uses the computed values from CSS.

- MinContent:
    - Containing blocks act as if they have 0 width.
    - All line breaking opportunities are taken.

- MaxContent:
    - Containing blocks act as if they have infinite width.
    - Only forced line breaks are accepted.

The above was based on a set of misunderstandings of CSS sizing.
A major problem with the above was that *all* containing blocks
behaved differently during intrinsic size layout, not just the
relevant one.

With this patch there are only two layout modes:

- Normal:
    - Everything uses the computed values from CSS.

- IntrinsicSizeDetermination:
    - One or more boxes have size constraints applied.

There are two size constraints per layout box, set here:

- FormattingState::NodeState::width_constraint
- FormattingState::NodeState::height_constraint

They are of type SizeConstraint and can be one of None, MinContent,
or MaxContent. The default is None.

When performing an IntrinsicSizeDetermination layout, we now assign
a size constraint to the box we're trying to determine the intrinsic
size of, which is then honored by using two new helpers to query
the dimensions of containing blocks:

- FormattingContext::containing_block_width_for(Box)
- FormattingContext::containing_block_height_for(Box)

If there's a relevant constraint in effect on the Box, the size of
its containing block is adjusted accordingly.

This is essentially an implementation of the "available space"
constraints from CSS-SIZING-3. I'm sure some things will break from
this, and we'll have to deal with that separately.

Spec: https://drafts.csswg.org/css-sizing-3/#available

1 files changed, 3 insertions, 3 deletions

diff --git a/Userland/Libraries/LibWeb/Layout/LineBuilder.h b/Userland/Libraries/LibWeb/Layout/LineBuilder.h
index 0f28cfeb81..8efdbc2e42 100644
--- a/Userland/Libraries/LibWeb/Layout/LineBuilder.h
+++ b/Userland/Libraries/LibWeb/Layout/LineBuilder.h
@@ -23,9 +23,9 @@ public:
     void append_text_chunk(TextNode const&, size_t offset_in_node, size_t length_in_node, float leading_size, float trailing_size, float leading_margin, float trailing_margin, float content_width, float content_height);
 
     // Returns whether a line break occurred.
-    bool break_if_needed(LayoutMode layout_mode, float next_item_width)
+    bool break_if_needed(float next_item_width)
     {
-        if (should_break(layout_mode, next_item_width)) {
+        if (should_break(next_item_width)) {
             break_line();
             return true;
         }
@@ -45,7 +45,7 @@ public:
 private:
     void begin_new_line(bool increment_y);
 
-    bool should_break(LayoutMode, float next_item_width);
+    bool should_break(float next_item_width);
 
     LineBox& ensure_last_line_box();