Fix #1057: make createImageBitmap throw when img has 0 size

Since the spec has no provisions for handling ImageBitmaps that
have no bitmap data, it is important to explicitly disallow
the creation of an ImageBitmap with a width or height of 0. With this
change, createImageBitmap will throw an exception when a source
image has a dimension of 0 *and* no crop rect is specified.

source

@@ -92297,8 +92297,17 @@ dictionary <dfn>ImageBitmapOptions</dfn> {
      return a promise rejected with an <code>InvalidStateError</code> exception and abort these
      steps.</p></li>
 
-     <li><p>If <var>image</var>'s media data has no intrinsic dimensions (e.g. it's a vector
-     graphic with no specified content size), then return a promise rejected with an
+     <li><p>If <var>image</var>'s media data has no <span>intrinsic dimensions</span> (e.g. it's a
+     vector graphic with no specified content size), then return a promise rejected with an
+     <code>InvalidStateError</code> exception and abort these steps.</p></li>
+
+     <li><p>If the <var>sw</var> and <var>sh</var> arguments are not specified and
+     <var>image</var>'s media data has both or either of its <span>intrinsic width</span> and
+     <span>intrinsic height</span> values equal to 0, then return a promise rejected with an
+     <code>InvalidStateError</code> exception and abort these steps.</p></li>
+
+     <li><p>If the <var>sh</var> argument is not specified and <var>image</var>'s media data has
+     an <span>intrinsic height</span> of 0, then return a promise rejected with an
      <code>InvalidStateError</code> exception and abort these steps.</p></li>
 
      <li><p>Create a new <code>ImageBitmap</code> object.</p></li>