Issue 5117 - Identify ElemHideEmulationFilters based on the filter text in the devtools panel

lib/devtools.js

Index: lib/devtools.js
===================================================================
--- a/lib/devtools.js
+++ b/lib/devtools.js
@@ -19,9 +19,7 @@
 
 const {RegExpFilter,
        WhitelistFilter,
-       ElemHideFilter,
-       ElemHideEmulationFilter} = require("filterClasses");
-
+       ElemHideFilter} = require("filterClasses");
 const {SpecialSubscription} = require("subscriptionClasses");
 const {FilterStorage} = require("filterStorage");
 const {defaultMatcher} = require("matcher");
@@ -150,10 +148,11 @@
  * Logs active element hiding filters to the devtools panel.
  *
  * @param {Page}     page       The page the elements were hidden on
- * @param {string[]} selectors  The CSS selectors of active elemhide filters
+ * @param {string[]} selectors  The selectors of applied ElemHideFilters
+ * @param {string[]} filters    The text of applied ElemHideEmulationFilters
  * @param {string}   docDomain  The IDN-decoded hostname of the document
  */
-function logHiddenElements(page, selectors, docDomain)
+function logHiddenElements(page, selectors, filters, docDomain)
 {
   let panel = getActivePanel(page);
   if (panel)
@@ -165,15 +164,16 @@
 
       for (let filter of subscription.filters)
       {
-        if (!(filter instanceof ElemHideFilter) &&
-            !(filter instanceof ElemHideEmulationFilter))
-          continue;
-        if (selectors.indexOf(filter.selector) == -1)
-          continue;
-        if (!filter.isActiveOnDomain(docDomain))
-          continue;
+        // We only know the exact filter in case of element hiding emulation.
+        // For regular element hiding filters, the content script only knows
+        // the selector, so we have to find a filter that has an identical
+        // selector and is active on the domain the match was reported from.
+        let isActiveElemHideFilter = filter instanceof ElemHideFilter &&
+                                     selectors.includes(filter.selector) &&
+                                     filter.isActiveOnDomain(docDomain);
 
-        addRecord(panel, {type: "ELEMHIDE", docDomain}, filter);
+        if (isActiveElemHideFilter || filters.includes(filter.text))
+          addRecord(panel, {type: "ELEMHIDE", docDomain}, filter);
       }
     }
   }
@@ -380,7 +380,7 @@
 port.on("devtools.traceElemHide", (message, sender) =>
 {
   logHiddenElements(
-    sender.page, message.selectors,
+    sender.page, message.selectors, message.filters,
     extractHostFromFrame(sender.frame)
   );
 });