fix(auto-render): concatenate content of successive text nodes

contrib/auto-render/auto-render.js

@@ -55,10 +55,29 @@ const renderElem = function(elem, optionsCopy) {
         const childNode = elem.childNodes[i];
         if (childNode.nodeType === 3) {
             // Text node
-            const frag = renderMathInText(childNode.textContent, optionsCopy);
+            // Concatenate all sibling text nodes.
+            // Webkit browsers split very large text nodes into smaller ones,
+            // so the delimiters may be split across different nodes.
+            let textContentConcat = childNode.textContent;
+            let sibling = childNode.nextSibling;
+            let nSiblings = 0;
+            while (sibling && (sibling.nodeType === 3)) {
+                textContentConcat += sibling.textContent;
+                sibling = sibling.nextSibling;
+                nSiblings++;
+            }
+            const frag = renderMathInText(textContentConcat, optionsCopy);
             if (frag) {
+                // Remove extra text nodes
+                for (let j = 0; j < nSiblings; j++) {
+                    childNode.nextSibling.remove();
+                }
                 i += frag.childNodes.length - 1;
                 elem.replaceChild(frag, childNode);
+            } else {
+                // If the concatenated text does not contain math
+                // the siblings will not either
+                i += nSiblings;
             }
         } else if (childNode.nodeType === 1) {
             // Element node