Introduce fromX static methods on DOMMatrixReadOnly. Fixes https://www.w3.org/Bugs/Public/show_bug.cgi?id=27493

Author: zcorpan

geometry/Overview.bs

@@ -395,6 +395,11 @@ In the following sections, terms have the following meaning:
 [Constructor(sequence<unrestricted double> numberSequence),
  Exposed=(Window,Worker)]
 interface DOMMatrixReadOnly {
+    [NewObject] static DOMMatrixReadOnly fromMatrix(optional DOMMatrixInit other);
+    [NewObject] static DOMMatrixReadOnly fromString(DOMString transformList);
+    [NewObject] static DOMMatrixReadOnly fromFloat32Array(Float32Array array32);
+    [NewObject] static DOMMatrixReadOnly fromFloat64Array(Float64Array array64);
+
     // These attributes are simple aliases for certain elements of the 4x4 matrix
     readonly attribute unrestricted double a;
     readonly attribute unrestricted double b;
@@ -636,49 +641,36 @@ with a sequence <var>numberSequence</var> of 16 elements, follow these steps:
 1. Set <a>is2D</a> to <code>false</code>.
 1. Return <var>matrix</var>
 
-<h3 id='dommatrixreadonly-constructors'>DOMMatrixReadOnly constructor</h3>
-
-The <dfn dfn-type=constructor dfn-for=DOMMatrixReadOnly><code>DOMMatrixReadOnly(<var>numberSequence</var>)</code></dfn> constructor, when invoked, must run the following steps:
-
-<dl class=switch>
-  <dt>If <var>numberSequence</var> has 6 elements</dt>
-  <dd>Return the result of invoking <a>create a 2d matrix</a> of type {{DOMMatrixReadOnly}} with the sequence <var>numberSequence</var>.</dd>
-  <dt>If <var>numberSequence</var> has 16 elements</dt>
-  <dd>Return the result of invoking <a>create a 3d matrix</a> of type {{DOMMatrixReadOnly}} with the sequence <var>numberSequence</var>.</dd>
-  <dt>Otherwise</dt>
-  <dd>Throw a <code>TypeError</code> exception.</dd>
-</dl>
-
-
-<h3 id='dommatrix-constructors'>DOMMatrix constructors</h3>
-
-The <dfn dfn-type=constructor dfn-for=DOMMatrix><code>DOMMatrix(<var>numberSequence</var>)</code></dfn> constructor, when invoked, must run the following steps:
+The <dfn dfn-type=constructor dfn-for=DOMMatrixReadOnly><code>DOMMatrixReadOnly(<var>numberSequence</var>)</code></dfn> and
+the <dfn dfn-type=constructor dfn-for=DOMMatrix><code>DOMMatrix(<var>numberSequence</var>)</code></dfn> constructors, when invoked, must run the following steps:
 
 <dl class=switch>
   <dt>If <var>numberSequence</var> has 6 elements</dt>
-  <dd>Return the result of invoking <a>create a 2d matrix</a> of type {{DOMMatrix}} with the sequence <var>numberSequence</var>.</dd>
+  <dd>Return the result of invoking <a>create a 2d matrix</a> of type {{DOMMatrixReadOnly}} or {{DOMMatrix}} as appropriate, with the sequence <var>numberSequence</var>.</dd>
   <dt>If <var>numberSequence</var> has 16 elements</dt>
-  <dd>Return the result of invoking <a>create a 3d matrix</a> of type {{DOMMatrix}} with the sequence <var>numberSequence</var>.</dd>
+  <dd>Return the result of invoking <a>create a 3d matrix</a> of type {{DOMMatrixReadOnly}} or {{DOMMatrix}} as appropriate, with the sequence <var>numberSequence</var>.</dd>
   <dt>Otherwise</dt>
   <dd>Throw a <code>TypeError</code> exception.</dd>
 </dl>
 
-The <dfn dfn-for=DOMMatrix id=dom-dommatrix-frommatrix><code>fromMatrix(<var>other</var>)</code></dfn> static method on {{DOMMatrix}} must follow these steps:
+The <dfn dfn-for=DOMMatrixReadOnly id=dom-dommatrixreadonly-frommatrix><code>fromMatrix(<var>other</var>)</code></dfn> static method on {{DOMMatrixReadOnly}} and
+the <dfn dfn-for=DOMMatrix id=dom-dommatrix-frommatrix><code>fromMatrix(<var>other</var>)</code></dfn> static method on {{DOMMatrix}} must follow these steps:
 
 <ol>
   <li><a>Validate and fixup</a> <var>other</var>.</li>
 
   <li>
     <dl class=switch>
       <dt>If the {{DOMMatrixInit/is2D}} dictionary member of <var>other</var> is <code>true</code></dt>
-      <dd>Return the result of invoking <a>create a 2d matrix</a> of type {{DOMMatrix}} with a sequence of numbers, the values being the 6 elements {{DOMMatrixInit/m11}}, {{DOMMatrixInit/m12}}, {{DOMMatrixInit/m21}}, {{DOMMatrixInit/m22}}, {{DOMMatrixInit/m41}} and {{DOMMatrixInit/m42}} of <var>other</var> in the given order.</dd>
+      <dd>Return the result of invoking <a>create a 2d matrix</a> of type {{DOMMatrixReadOnly}} or {{DOMMatrix}} as appropriate, with a sequence of numbers, the values being the 6 elements {{DOMMatrixInit/m11}}, {{DOMMatrixInit/m12}}, {{DOMMatrixInit/m21}}, {{DOMMatrixInit/m22}}, {{DOMMatrixInit/m41}} and {{DOMMatrixInit/m42}} of <var>other</var> in the given order.</dd>
       <dt>Otherwise</dt>
-      <dd>Return the result of invoking <a>create a 3d matrix</a> of type {{DOMMatrix}} with a sequence of numbers, the values being the 16 elements {{DOMMatrixInit/m11}}, {{DOMMatrixInit/m12}}, {{DOMMatrixInit/m13}}, ..., {{DOMMatrixInit/m44}} of <var>other</var> in the given order.</dd>
+      <dd>Return the result of invoking <a>create a 3d matrix</a> of type {{DOMMatrixReadOnly}} or {{DOMMatrix}} as appropriate, with a sequence of numbers, the values being the 16 elements {{DOMMatrixInit/m11}}, {{DOMMatrixInit/m12}}, {{DOMMatrixInit/m13}}, ..., {{DOMMatrixInit/m44}} of <var>other</var> in the given order.</dd>
     </dl>
   </li>
 </ol>
 
-The <dfn dfn-for=DOMMatrix><code>fromString(<var>transformList</var>)</code></dfn> static method on {{DOMMatrix}} must follow these steps:
+The <dfn dfn-for=DOMMatrixReadOnly><code>fromString(<var>transformList</var>)</code></dfn> static method on {{DOMMatrixReadOnly}} and
+the <dfn dfn-for=DOMMatrix><code>fromString(<var>transformList</var>)</code></dfn> static method on {{DOMMatrix}} must follow these steps:
 
 <ol>
   <li>Parse <var>transformList</var> by following the syntax description in “<a href=http://www.w3.org/TR/css-transforms-1/#svg-syntax>Syntax of the SVG ‘transform’ attribute</a>” [[!CSS3-TRANSFORMS]] to a <<transform-list>>. If parsing is not successful or any <<transform-function>> has <<length>> values without <a spec='css-values'>absolute length</a> units<!--For WD: <a spec='css-values-3'>absolute length units</a>-->, throw a {{SyntaxError}} exception.</li>
@@ -695,31 +687,33 @@ The <dfn dfn-for=DOMMatrix><code>fromString(<var>transformList</var>)</code></df
   <li>
     <dl class=switch>
       <dt>If <var>2dTransform</var> is set to <code>true</code></dt>
-      <dd>Return the result of invoking <a>create a 2d matrix</a> of type {{DOMMatrix}} with a sequence of numbers, the values being the elements <var>m11</var>, <var>m12</var>, <var>21</var>, <var>m22</var>, <var>m41</var> and <var>m42</var> of <var>matrix</var> of <var>matrix</var>.</dd>
+      <dd>Return the result of invoking <a>create a 2d matrix</a> of type {{DOMMatrixReadOnly}} or {{DOMMatrix}} as appropriate, with a sequence of numbers, the values being the elements <var>m11</var>, <var>m12</var>, <var>21</var>, <var>m22</var>, <var>m41</var> and <var>m42</var> of <var>matrix</var> of <var>matrix</var>.</dd>
       <dt>If <var>2dTransform</var> is set to <code>false</code></dt>
-      <dd>Return the result of invoking <a>create a 3d matrix</a> of type {{DOMMatrix}} with a sequence of numbers, the values being the 16 elements of <var>matrix</var>.</dd>
+      <dd>Return the result of invoking <a>create a 3d matrix</a> of type {{DOMMatrixReadOnly}} or {{DOMMatrix}} as appropriate, with a sequence of numbers, the values being the 16 elements of <var>matrix</var>.</dd>
     </dl>
   </li>
 </ol>
 
-The <dfn dfn-for=DOMMatrix><code>fromFloat32Array(<var>array32</var>)</code></dfn> static method on {{DOMMatrix}} must follow these steps:
+The <dfn dfn-for=DOMMatrixReadOnly><code>fromFloat32Array(<var>array32</var>)</code></dfn> static method on {{DOMMatrixReadOnly}} and
+the <dfn dfn-for=DOMMatrix><code>fromFloat32Array(<var>array32</var>)</code></dfn> static method on {{DOMMatrix}} must follow these steps:
 
 <dl class=switch>
   <dt>If <var>array32</var> has 6 elements</dt>
-  <dd>Return the result of invoking <a>create a 2d matrix</a> of type {{DOMMatrix}} with a sequence of numbers taking the values from <var>array32</var> in the provided order.</dd>
+  <dd>Return the result of invoking <a>create a 2d matrix</a> of type {{DOMMatrixReadOnly}} or {{DOMMatrix}} as appropriate, with a sequence of numbers taking the values from <var>array32</var> in the provided order.</dd>
   <dt>If <var>array32</var> has 16 elements</dt>
-  <dd>Return the result of invoking <a>create a 3d matrix</a> of type {{DOMMatrix}} with a sequence of numbers taking the values from <var>array32</var> in the provided order.</dd>
+  <dd>Return the result of invoking <a>create a 3d matrix</a> of type {{DOMMatrixReadOnly}} or {{DOMMatrix}} as appropriate, with a sequence of numbers taking the values from <var>array32</var> in the provided order.</dd>
   <dt>Otherwise</dt>
   <dd>Throw a <code>TypeError</code> exception.</dd>
 </dl>
 
-The <dfn dfn-for=DOMMatrix><code>fromFloat64Array(<var>array64</var>)</code></dfn> static method on {{DOMMatrix}} must follow these steps:
+The <dfn dfn-for=DOMMatrixReadOnly><code>fromFloat64Array(<var>array64</var>)</code></dfn> static method on {{DOMMatrixReadOnly}} and
+the <dfn dfn-for=DOMMatrix><code>fromFloat64Array(<var>array64</var>)</code></dfn> static method on {{DOMMatrix}} must follow these steps:
 
 <dl class=switch>
   <dt>If <var>array64</var> has 6 elements</dt>
-  <dd>Return the result of invoking <a>create a 2d matrix</a> of type {{DOMMatrix}} with a sequence of numbers taking the values from <var>array64</var> in the provided order.</dd>
+  <dd>Return the result of invoking <a>create a 2d matrix</a> of type {{DOMMatrixReadOnly}} or {{DOMMatrix}} as appropriate, with a sequence of numbers taking the values from <var>array64</var> in the provided order.</dd>
   <dt>If <var>array32</var> has 16 elements</dt>
-  <dd>Return the result of invoking <a>create a 3d matrix</a> of type {{DOMMatrix}} with a sequence of numbers taking the values from <var>array64</var> in the provided order.</dd>
+  <dd>Return the result of invoking <a>create a 3d matrix</a> of type {{DOMMatrixReadOnly}} or {{DOMMatrix}} as appropriate, with a sequence of numbers taking the values from <var>array64</var> in the provided order.</dd>
   <dt>Otherwise</dt>
   <dd>Throw a <code>TypeError</code> exception.</dd>
 </dl>