Ignore overflow_wrap: break-word when calculating min-content width

See https://drafts.csswg.org/css-text-3/#overflow-wrap-property

Fix #582.

weasyprint/layout/preferred.py

@@ -252,7 +252,8 @@ def inline_line_widths(context, box, outer, is_line_start, minimum,
                     _, _, new_resume_at, width, _, _ = (
                         text.split_first_line(
                             child_text[resume_at:], child.style, context,
-                            max_width, child.justification_spacing))
+                            max_width, child.justification_spacing,
+                            minimum=True))
                     lines.append(width)
                     if first_line:
                         break

weasyprint/text.py

@@ -909,7 +909,8 @@ def add_attr(start, end, spacing):
     return layout
 
 
-def split_first_line(text, style, context, max_width, justification_spacing):
+def split_first_line(text, style, context, max_width, justification_spacing,
+                     minimum=False):
     """Fit as much as possible in the available width for one line of text.
 
     Return ``(layout, length, resume_at, width, height, baseline)``.
@@ -1122,7 +1123,7 @@ def split_first_line(text, style, context, max_width, justification_spacing):
     first_line_width, _ = get_size(first_line, style)
     space = max_width - first_line_width
     # If we can break words and the first line is too long
-    if overflow_wrap == 'break-word' and space < 0:
+    if not minimum and overflow_wrap == 'break-word' and space < 0:
         # Is it really OK to remove hyphenation for word-break ?
         hyphenated = False
         # TODO: Modify code to preserve W3C condition: