Update spec for setAttribute and setAttributeNS to correctly account for the attribute identity changing from the default policy.

Author: lukewarlow

dom.bs

@@ -6678,50 +6678,37 @@ string <var>namespace</var> (default null):</p>
 
 <div algorithm>
 <p>To <dfn export id=concept-element-attributes-set-value>set an attribute value</dfn> given an
-<a for=/>element</a> <var>element</var>, a string <var>localName</var>, a string or {{TrustedType}}
-<var>value</var>, an optional null or string <var>prefix</var> (default null), an optional null or
-string <var>namespace</var> (default null), and an optional boolean <var>verify</var> (default
-false):
+<a for=/>element</a> <var>element</var>, a string <var>localName</var>, a string <var>value</var>,
+an optional null or string <var>prefix</var> (default null), and an optional null or string
+<var>namespace</var> (default null):
 
 <ol>
- <li>Let <var>attribute</var> be the result of
+ <li><p>Let <var>attribute</var> be the result of
  <a lt="get an attribute by namespace and local name">getting an attribute</a> given
  <var>namespace</var>, <var>localName</var>, and <var>element</var>.
 
- <li><p>Let <var>attributeExists</var> be false if <var>attribute</var> is null; otherwise true.
-
- <li><p>If <var>attributeExists</var> is false, then set <var>attribute</var> to an <a>attribute</a>
- whose <a for=Attr>namespace</a> is <var>namespace</var>, <a for=Attr>namespace prefix</a> is
+ <li><p>If <var>attribute</var> is null, then set attribute to an <a>attribute</a> whose
+ <a for=Attr>namespace</a> is <var>namespace</var>, <a for=Attr>namespace prefix</a> is
  <var>prefix</var>, <a for=Attr>local name</a> is <var>localName</var>, <a for=Attr>value</a> is
  <var>value</var>, and <a for=Node>node document</a> is <var>element</var>'s
  <a for=Node>node document</a>.
 
- <li><p>Let <var>verifiedValue</var> be <var>value</var>.
-
- <li>
-  <p>If <var>verify</var> is true:
-
-  <ol>
-   <li><p>Set <var>verifiedValue</var> to the result of
-   <a lt="verify attribute value">verifying an attribute value</a> given <var>value</var>,
-   <var>attribute</var>, and <var>element</var>.
-
-   <li><p>Set <var>attributeExists</var> to true if <var>element</var>
-   <a lt="has an attribute">has an attribute</a> <var>attribute</var>; otherwise false.
-  </ol>
- </li>
-
- <li><p>If <var>attributeExists</var> is true, <a lt="change an attribute">change</a>
- <var>attribute</var> to <var>verifiedValue</var>.
+ <li><p>Let <var>verifiedValue</var> be the result of
+ <a lt="verify attribute value">verifying an attribute value</a> given <var>value</var>,
+ <var>attribute</var>, and <var>element</var>.
 
- <li>
-  <p>Otherwise:
+ <li><p>Set <var>attribute</var> to the result of
+ <a lt="get an attribute by namespace and local name">getting an attribute</a> given
+ <var>namespace</var>, <var>localName</var>, and <var>element</var>.
 
-  <ol>
-   <li><p>Set <var>attribute</var>'s <a for=Attr>value</a> to <var>verifiedValue</var>.
+ <li><p>If <var>attribute</var> is null, create an <a>attribute</a> whose <a for=Attr>namespace</a>
+ is <var>namespace</var>, <a for=Attr>namespace prefix</a> is <var>prefix</var>,
+ <a for=Attr>local name</a> is <var>localName</var>, <a for=Attr>value</a> is
+ <var>verifiedValue</var>, and <a for=Node>node document</a> is <var>element</var>'s
+ <a for=Node>node document</a>, then <a lt="append an attribute">append</a> this <a>attribute</a> to
+ <var>element</var>, and then return.
 
-   <li><p><a lt="append an attribute">Append</a> this <a>attribute</a> to <var>element</var>.
-  </ol>
+ <li><p><a lt="change an attribute">Change</a> <var>attribute</var> to <var>verifiedValue</var>.
 </ol>
 </div>
 
@@ -6980,32 +6967,26 @@ method steps are:
  <li><p>Let <var>attribute</var> be the first <a>attribute</a> in <a>this</a>'s
  <a for=Element>attribute list</a> whose <a for=Attr>qualified name</a> is <var>qualifiedName</var>,
  and null otherwise.
- <!-- This is step 2 of "get an attribute by name", modified as appropriate -->
-
- <li><p>Let <var>attributeExists</var> be false if <var>attribute</var> is null; otherwise true.
 
- <li><p>If <var>attributeExists</var> is false, then set <var>attribute</var> to an <a>attribute</a>
+ <li><p>If <var>attribute</var> is null, then set <var>attribute</var> to an <a>attribute</a>
  whose <a for=Attr>local name</a> is <var>qualifiedName</var>, <a for=Attr>value</a> is
  <var>value</var>, and <a for=Node>node document</a> is <a>this</a>'s <a for=Node>node document</a>.
 
  <li><p>Let <var>verifiedValue</var> be the result of
  <a lt="verify attribute value">verifying an attribute value</a> given <var>value</var>,
  <var>attribute</var>, and <a>this</a>.
 
- <li><p>Set <var>attributeExists</var> to true if <a>this</a>
- <a lt="has an attribute">has an attribute</a> <var>attribute</var>; otherwise false.
-
- <li><p>If <var>attributeExists</var> is true, <a lt="change an attribute">change</a>
- <var>attribute</var> to <var>verifiedValue</var>.
-
- <li>
-  <p>Otherwise:
+ <li><p>Set <var>attribute</var> to the first <a>attribute</a> in <a>this</a>'s
+ <a for=Element>attribute list</a> whose <a for=Attr>qualified name</a> is <var>qualifiedName</var>,
+ and null otherwise.
 
-  <ol>
-   <li><p>Set <var>attribute</var>'s <a for=Attr>value</a> to <var>verifiedValue</var>.
+ <li><p>If <var>attribute</var> is null, create an <a>attribute</a> whose
+ <a for=Attr>local name</a> is <var>qualifiedName</var>, <a for=Attr>value</a> is
+ <var>verifiedValue</var>, and <a for=Node>node document</a> is <a>this</a>'s
+ <a for=Node>node document</a>, then <a lt="append an attribute">append</a> this <a>attribute</a>
+ to <a>this</a>, and then return.
 
-   <li><p><a lt="append an attribute">Append</a> this <a>attribute</a> to <var>element</var>.
-  </ol>
+ <li><p><a lt="change an attribute">Change</a> <var>attribute</var> to <var>verifiedValue</var>.
 </ol>
 
 <p>The