[css-transitions] Have clearer wording about elements not in the document, rather than trying to define them as not having computed style.

Author: dbaron

css-transitions/Overview.bs

@@ -533,6 +533,13 @@ url: http://w3c.github.io/dom/#constructing-events; type: dfn; text: event const
         </span>
       </p>
 
+      <p>
+        If an element is no longer in the document,
+        implementations must remove transitions on it
+        from the <a>running transitions</a> and the
+        <a>completed transitions</a>.
+      </p>
+
       <div class="note">
 
         <p>
@@ -564,9 +571,6 @@ url: http://w3c.github.io/dom/#constructing-events; type: dfn; text: event const
       <p>
         Various things can cause the computed style of an element to change,
         or for an element to start or stop having computed style.
-        (For the purposes of this specification,
-        an element has computed style when it is in the document tree,
-        and does not have computed style when it is not in the document tree.)
         These include
         insertion and removal of elements from the document tree
         (which both changes whether those elements have computed styles and
@@ -587,6 +591,8 @@ url: http://w3c.github.io/dom/#constructing-events; type: dfn; text: event const
         However,
         when an implementation updates the computed style for an element
         to reflect one of these changes,
+        or computes the computed style for an element
+        newly added to the document,
         it must update the computed style for all elements to reflect all
         of these changes at the same time
         (or at least it must be undetectable that it was done at a
@@ -614,8 +620,9 @@ url: http://w3c.github.io/dom/#constructing-events; type: dfn; text: event const
         When a <a>style change event</a> occurs,
         implementations must start transitions based on
         the computed styles that changed in that event.
-        If an element does not have a computed style
-        either before or after the style change event,
+        If an element is not in the document during that
+        style change even or was not in the document during
+        the previous style change event,
         then transitions are not started for that element
         in that style change event.
         Otherwise,

css-transitions/Overview.html

@@ -917,6 +917,14 @@ <h2 class="heading settled" data-level="3" id="starting"><span class="secno">3.
       </p>
 
 
+   <p>
+        If an element is no longer in the document,
+        implementations must remove transitions on it
+        from the <a data-link-type="dfn" href="#running-transition">running transitions</a> and the
+        <a data-link-type="dfn" href="#completed-transition">completed transitions</a>.
+      </p>
+
+      
    <div class="note" role="note">
 
 
@@ -954,9 +962,6 @@ <h2 class="heading settled" data-level="3" id="starting"><span class="secno">3.
    <p>
         Various things can cause the computed style of an element to change,
         or for an element to start or stop having computed style.
-        (For the purposes of this specification,
-        an element has computed style when it is in the document tree,
-        and does not have computed style when it is not in the document tree.)
         These include
         insertion and removal of elements from the document tree
         (which both changes whether those elements have computed styles and
@@ -977,6 +982,8 @@ <h2 class="heading settled" data-level="3" id="starting"><span class="secno">3.
         However,
         when an implementation updates the computed style for an element
         to reflect one of these changes,
+        or computes the computed style for an element
+        newly added to the document,
         it must update the computed style for all elements to reflect all
         of these changes at the same time
         (or at least it must be undetectable that it was done at a
@@ -1006,8 +1013,9 @@ <h2 class="heading settled" data-level="3" id="starting"><span class="secno">3.
         When a <a data-link-type="dfn" href="#style-change-event">style change event</a> occurs,
         implementations must start transitions based on
         the computed styles that changed in that event.
-        If an element does not have a computed style
-        either before or after the style change event,
+        If an element is not in the document during that
+        style change even or was not in the document during
+        the previous style change event,
         then transitions are not started for that element
         in that style change event.
         Otherwise,