[css-grid] Add dense packing.

Author: tabatkins

css-grid/Overview.html

@@ -1663,10 +1663,10 @@ <h4 data-level=6.2.1 id=auto-placement-algo><span class=secno>6.2.1 </span><span
 							and return to the previous step.
 					</ol>
 			</dl>
-	</ol>
 
-	<p class=issue>
-		Edit the algorithm to allow for dense packing.
+<p>			If <a class=property data-link-type=propdesc href=#propdef-grid-auto-flow title=grid-auto-flow>grid-auto-flow</a> specifies the <a class=css data-link-type=maybe href=#valuedef-dense>dense</a> keyword,
+			reset the <a href=#auto-placement-cursor>auto-placement cursor</a> to 1/1 each time an item is placed.
+	</ol>
 
 <h3 data-level=6.3 id=grid-auto-position-property><span class=secno>6.3 </span><span class=content>
 Default Position: the <a class=property data-link-type=propdesc href=#propdef-grid-auto-position title=grid-auto-position>grid-auto-position</a> property</span><a class=section-link href=#grid-auto-position-property>§</a></h3>

css-grid/Overview.src.html

@@ -1658,10 +1658,10 @@ <h4 id='auto-placement-algo'>
 							and return to the previous step.
 					</ol>
 			</dl>
-	</ol>
 
-	<p class='issue'>
-		Edit the algorithm to allow for dense packing.
+			If 'grid-auto-flow' specifies the ''dense'' keyword,
+			reset the <a>auto-placement cursor</a> to 1/1 each time an item is placed.
+	</ol>
 
 <h3 id="grid-auto-position-property">
 Default Position: the 'grid-auto-position' property</h3>