Make arguments to insertAdjacent{Text,Element} non-optional

LayoutTests/fast/dynamic/insertAdjacentText.html

Index: LayoutTests/fast/dynamic/insertAdjacentText.html
diff --git a/LayoutTests/fast/dynamic/insertAdjacentText.html b/LayoutTests/fast/dynamic/insertAdjacentText.html
index a8b9ab60127c3341210e38c1ec3891bbe73e32ff..60c3e2523efeb75e60d6034101d88f3c81ff4125 100644
--- a/LayoutTests/fast/dynamic/insertAdjacentText.html
+++ b/LayoutTests/fast/dynamic/insertAdjacentText.html
@@ -20,8 +20,9 @@
       var testPassed = false;
       try {
          func();
+         document.getElementById("error-log").textContent += "Expected exception missing.\n";
       } catch (e) {
-         document.getElementById("error-log").innerHTML += "Caught expected exception: " + e + "\n";
+         document.getElementById("error-log").textContent += "Caught expected exception: " + e + "\n";
          testPassed = true;
       }
       return testPassed;
@@ -29,10 +30,20 @@
 
    // check that exceptions are thrown as required
    var passes = true;
-   passes = passes & assertThrows(function() {
-      // should throw TYPE_MISMATCH_ERR
+   passes = assertThrows(function() {
+      // should throw SyntaxError
       document.getElementById("container").insertAdjacentText("blah", "text");
-   });
+   }) && passes;
+
+   passes = assertThrows(function() {
+      // should throw TypeError
+      document.getElementById("container").insertAdjacentText();
+   }) && passes;
+
+   passes = assertThrows(function() {
+      // should throw TypeError
+      document.getElementById("container").insertAdjacentText("afterBegin");
+   }) && passes;
 
    if (passes) {
       document.getElementById("status").style.color = "green";