Add `CheckObjectCoercible` for the `String.prototype` HTML methods

src/string.js

Index: src/string.js
diff --git a/src/string.js b/src/string.js
index 0d5ed0fc4297c49b0f79917de5a9e6b6a2758c4d..5cd1c0cfb71fc2edbe62b91960af7e2708ce0c43 100644
--- a/src/string.js
+++ b/src/string.js
@@ -706,7 +706,7 @@ function StringSubstring(start, end) {
 }
 
 
-// This is not a part of ECMA-262.
+// ES6 draft, revision 26 (2014-07-18), section B.2.3.1
 function StringSubstr(start, n) {
   CHECK_OBJECT_COERCIBLE(this, "String.prototype.substr");
 
@@ -827,7 +827,7 @@ function StringFromCharCode(code) {
 }
 
 
-// Helper function for very basic XSS protection.
+// ES6 draft, revision 26 (2014-07-18), section B.2.3.2.1
 function HtmlEscape(str) {
   return TO_STRING_INLINE(str).replace(/</g, "&lt;")
                               .replace(/>/g, "&gt;")
@@ -836,69 +836,93 @@ function HtmlEscape(str) {
 }
 
 
-// Compatibility support for KJS.
-// Tested by mozilla/js/tests/js1_5/Regress/regress-276103.js.
-function StringLink(s) {
-  return "<a href=\"" + HtmlEscape(s) + "\">" + this + "</a>";
-}
-
-
+// ES6 draft, revision 26 (2014-07-18), section B.2.3.2
 function StringAnchor(name) {
+  CHECK_OBJECT_COERCIBLE(this, "String.prototype.anchor");
   return "<a name=\"" + HtmlEscape(name) + "\">" + this + "</a>";
 }
 
 
-function StringFontcolor(color) {
-  return "<font color=\"" + HtmlEscape(color) + "\">" + this + "</font>";
-}
-
-
-function StringFontsize(size) {
-  return "<font size=\"" + HtmlEscape(size) + "\">" + this + "</font>";
-}
-
-
+// ES6 draft, revision 26 (2014-07-18), section B.2.3.3
 function StringBig() {
+  CHECK_OBJECT_COERCIBLE(this, "String.prototype.big");
   return "<big>" + this + "</big>";
 }
 
 
+// ES6 draft, revision 26 (2014-07-18), section B.2.3.4
 function StringBlink() {
+  CHECK_OBJECT_COERCIBLE(this, "String.prototype.blink");
   return "<blink>" + this + "</blink>";
 }
 
 
+// ES6 draft, revision 26 (2014-07-18), section B.2.3.5
 function StringBold() {
+  CHECK_OBJECT_COERCIBLE(this, "String.prototype.bold");
   return "<b>" + this + "</b>";
 }
 
 
+// ES6 draft, revision 26 (2014-07-18), section B.2.3.6
 function StringFixed() {
+  CHECK_OBJECT_COERCIBLE(this, "String.prototype.fixed");
   return "<tt>" + this + "</tt>";
 }
 
 
+// ES6 draft, revision 26 (2014-07-18), section B.2.3.7
+function StringFontcolor(color) {
+  CHECK_OBJECT_COERCIBLE(this, "String.prototype.fontcolor");
+  return "<font color=\"" + HtmlEscape(color) + "\">" + this + "</font>";
+}
+
+
+// ES6 draft, revision 26 (2014-07-18), section B.2.3.8
+function StringFontsize(size) {
+  CHECK_OBJECT_COERCIBLE(this, "String.prototype.fontsize");
+  return "<font size=\"" + HtmlEscape(size) + "\">" + this + "</font>";
+}
+
+
+// ES6 draft, revision 26 (2014-07-18), section B.2.3.9
 function StringItalics() {
+  CHECK_OBJECT_COERCIBLE(this, "String.prototype.italics");
   return "<i>" + this + "</i>";
 }
 
 
+// ES6 draft, revision 26 (2014-07-18), section B.2.3.10
+function StringLink(s) {
+  CHECK_OBJECT_COERCIBLE(this, "String.prototype.link");
+  return "<a href=\"" + HtmlEscape(s) + "\">" + this + "</a>";
+}
+
+
+// ES6 draft, revision 26 (2014-07-18), section B.2.3.11
 function StringSmall() {
+  CHECK_OBJECT_COERCIBLE(this, "String.prototype.small");
   return "<small>" + this + "</small>";
 }
 
 
+// ES6 draft, revision 26 (2014-07-18), section B.2.3.12
 function StringStrike() {
+  CHECK_OBJECT_COERCIBLE(this, "String.prototype.strike");
   return "<strike>" + this + "</strike>";
 }
 
 
+// ES6 draft, revision 26 (2014-07-18), section B.2.3.13
 function StringSub() {
+  CHECK_OBJECT_COERCIBLE(this, "String.prototype.sub");
   return "<sub>" + this + "</sub>";
 }
 
 
+// ES6 draft, revision 26 (2014-07-18), section B.2.3.14
 function StringSup() {
+  CHECK_OBJECT_COERCIBLE(this, "String.prototype.sup");
   return "<sup>" + this + "</sup>";
 }