Editorial: use "transient activation" instead of obsolete concept

Fixes #160.

Author: foolip

fullscreen.bs

@@ -126,15 +126,6 @@ these steps:
 <p><dfn>Fullscreen is supported</dfn> if there is no previously-established user preference,
 security risk, or platform limitation.
 
-<p>An algorithm is <dfn>allowed to request fullscreen</dfn> if one of the following is true:
-
- <ul>
-  <li><p>The algorithm is <a>triggered by user activation</a>.
-
-  <li><p>The algorithm is <a>triggered by a user generated orientation change</a>.
- </ul>
-<!-- cross-process -->
-
 <hr>
 
 <p>To <dfn>run the fullscreen steps</dfn> for a <a>document</a> <var>document</var>, run these
@@ -267,7 +258,8 @@ when invoked, must run these steps:
 
    <li><p><a>Fullscreen is supported</a>.
 
-   <li><p>This algorithm is <a>allowed to request fullscreen</a>.
+   <li><p><var>pending</var>'s <a>relevant global object</a> has <a>transient activation</a> or the
+   algorithm is <a>triggered by a user generated orientation change</a>.
   </ul>
 
  <li><p>Return <var>promise</var>, and run the remaining steps <a>in parallel</a>.