[giowr] (2) Mention that for rel=icon UAs should also use type=''; me…

…ntion what to do when an icon sucks; mention how to handle missing sizes=''.

git-svn-id: http://svn.whatwg.org/webapps@1713 340c8d12-0b0e-0410-8428-c7bf67bfef74

index

 
   <p>Icons could be auditory icons, visual icons, or other kinds of icons. If
    multiple icons are provided, the user agent must select the most
-   appropriate icon according to the <code title=attr-link-media><a
-   href="#media0">media</a></code> and <code title=attr-link-sizes><a
+   appropriate icon according to the <code title=attr-link-type><a
+   href="#type">type</a></code>, <code title=attr-link-media><a
+   href="#media0">media</a></code>, and <code title=attr-link-sizes><a
    href="#sizes0">sizes</a></code> attributes. If there are multiple equally
    appropriate icons, user agents must use the last one declared in <a
-   href="#tree-order">tree order</a>.
+   href="#tree-order">tree order</a>. If the user agent tries to use an icon
+   but that icon is determined, upon closer examination, to in fact be
+   inappropriate (e.g. because it uses an unsupported format), then the user
+   agent must try the next-most-appropriate icon as determined by the
+   attributes.
 
   <p>There is no default type for resources given by the <code
    title=rel-icon><a href="#icon3">icon</a></code> keyword.</p>
    href="#sizes0">sizes</a></code> attribute must not represent icon sizes
    that are not actually available in the linked resource.
 
+  <p>If the attribute is not specified, then the user agent must assume that
+   the given icon is appropriate, but less appropriate than an icon of a
+   known and appropriate size.
+
   <div class=example>
    <p>The following snippet shows the top part of an application with several
     icons.</p>

source

   <p>Icons could be auditory icons, visual icons, or other kinds of
   icons. If multiple icons are provided, the user agent must select
   the most appropriate icon according to the <code
-  title="attr-link-media">media</code> and <code
+  title="attr-link-type">type</code>, <code
+  title="attr-link-media">media</code>, and <code
   title="attr-link-sizes">sizes</code> attributes. If there are
   multiple equally appropriate icons, user agents must use the last
-  one declared in <span>tree order</span>.</p>
+  one declared in <span>tree order</span>. If the user agent tries to
+  use an icon but that icon is determined, upon closer examination, to
+  in fact be inappropriate (e.g. because it uses an unsupported
+  format), then the user agent must try the next-most-appropriate icon
+  as determined by the attributes.</p>
 
   <p>There is no default type for resources given by the <code
   title="rel-icon">icon</code> keyword.</p> <!-- XXX we don't define
   icon sizes that are not actually available in the linked
   resource.</p>
 
+  <p>If the attribute is not specified, then the user agent must
+  assume that the given icon is appropriate, but less appropriate than
+  an icon of a known and appropriate size.</p>
+
   <div class="example">
 
    <p>The following snippet shows the top part of an application with