[css-text] Add 'line-break: anywhere'. Fixes w3c#1171, fixes w3c#1561.

Author: frivoal

css-text/Overview.bs

@@ -20,6 +20,7 @@ At Risk: the <length> values of the 'tab-size' property
 At Risk: the 'text-justify' property
 At Risk: the percentage values of 'word-spacing'
 At Risk: the 'hanging-punctuation' property
+At Risk: the ''line-break/anywhere'' value of the 'line-break' property
 Ignored Vars: letter-spacing
 </pre>
 <pre class=link-defaults>
@@ -878,6 +879,9 @@ Line Breaking Details</h3>
         the text consists predominantly of CJK characters with only short non-CJK excerpts,
         and it is desired that the text be better distributed on each line.</dd>
 
+	Note: This value does not affect whether there are <a>soft wrap opportunities</a> around punctuation characters.
+	To allow breaks anywhere, see ''line-break: anywhere''.
+
       <dt><dfn>break-word</dfn></dt>
       <dd>An otherwise unbreakable sequence of <a>characters</a>
         may be broken at an arbitrary point if
@@ -933,16 +937,16 @@ Line Breaking Details</h3>
     </div>
 
     <p>When shaping scripts such as Arabic
-      are allowed to break within words due to ''break-all'' or ''word-break/break-word'',
+      are allowed to break within words due to ''word-break/break-all'' or ''word-break/break-word'',
       the characters must still be shaped
       as if the word were <a href="#word-break-shaping">not broken</a>.
 
   <h3 id="line-break-property">
-    Breaking Rules for Punctuation: the 'line-break' property</h3>
+    Line Breaking Rules: the 'line-break' property</h3>
 
     <pre class="propdef">
     Name: line-break
-    Value: auto | loose | normal | strict
+    Value: auto | loose | normal | strict | anywhere
     Initial: auto
     Inherited: yes
     Canonical order: n/a
@@ -966,6 +970,15 @@ Line Breaking Details</h3>
       <dt><dfn>strict</dfn></dt>
       <dd>Breaks text using the most stringent set of line-breaking
         rules.</dd>
+      <dt><dfn>anywhere</dfn></dt>
+      <dd>There is a <a>soft wrap opportunity</a> around every <a>typographic character unit</a>,
+      including around any punctuation character or preserved spaces,
+      or in the middle of words,
+      disregarding any prohibition against line breaks introduced by characters with the GL, JW, or ZJW character class (see [[UAX14]]).
+      The different wrapping opportunities must not be prioritized.
+      Hyphenation is not applied.
+
+      Note: This value triggers the line breaking rules typically seen in terminals.</dd>
     </dl>
 
     <p class="feedback issue">
@@ -974,9 +987,9 @@ Line Breaking Details</h3>
       However, the resulting behavior could use some review and feedback to make sure they are correct,
       particularly when “word basis” breaking is used (''word-break: keep-all'') in Korean.
 
-    <p>CSS distinguishes between three levels of strictness in the rules for
+    <p>CSS distinguishes between four levels of strictness in the rules for
       text wrapping.
-      The precise set of rules in effect for each level is up to the UA
+      The precise set of rules in effect for each of ''line-break/loose'', ''line-break/normal'', and ''line-break/strict'' is up to the UA
       and should follow language conventions.
       However, this specification does require that:</p>
 
@@ -1215,6 +1228,7 @@ Shaping Across Intra-word Breaks</h3>
   (such as when breaking due to
   ''word-break: break-all'',
   ''word-break: break-word'',
+  ''line-break: anywhere'',
   ''overflow-wrap: break-word'',
   or when <a>hyphenating</a>)
   the characters must still be shaped
@@ -2383,6 +2397,7 @@ Changes</h2>
     <li>Qualified that only lowercase letters are titlecased for ''text-transform: capitalize''; uppercase letters remain unaffected.
     <li>For ''word-break: break-all'', switched to UAX14 notion of “letters”,
         since that handles symbols better.
+    <li>Added ''line-break: anywhere''.
   </ul>
 
   <h3 class="no-num" id="changes-2013">