Issue 7284 - Move CSS escaping to createStyleSheet

lib/content/elemHideEmulation.js

Index: lib/content/elemHideEmulation.js
===================================================================
--- a/lib/content/elemHideEmulation.js
+++ b/lib/content/elemHideEmulation.js
@@ -344,18 +344,17 @@
 
 class ContainsSelector
 {
   constructor(textContent)
   {
     this.dependsOnDOM = true;
     this.dependsOnCharacterData = true;
 
-    this._regexp = makeRegExpParameter(
-      textContent.replace("\\7B ", "{").replace("\\7D ", "}"));
+    this._regexp = makeRegExpParameter(textContent);
   }
 
   *getSelectors(prefix, subtree, styles, targets)
   {
     for (let element of this.getElements(prefix, subtree, styles, targets))
       yield [makeSelector(element), subtree];
   }
 
@@ -407,18 +406,17 @@
   {
     this.dependsOnStyles = true;
     this.dependsOnDOM = true;
 
     let regexpString;
     if (propertyExpression.length >= 2 && propertyExpression[0] == "/" &&
         propertyExpression[propertyExpression.length - 1] == "/")
     {
-      regexpString = propertyExpression.slice(1, -1)
-        .replace("\\7B ", "{").replace("\\7D ", "}");
+      regexpString = propertyExpression.slice(1, -1);
     }
     else
       regexpString = filterToRegExp(propertyExpression);
 
     this._regexp = new RegExp(regexpString, "i");
   }
 
   *findPropsSelectors(styles, prefix, regexp)