Fine tune cosmetic filtering badge-related code

Related issue:
- https://github.com/uBlockOrigin/uBlock-issues/issues/756

As per feedback:
- https://github.com/uBlockOrigin/uBlock-issues/issues/756#issuecomment-549128106

src/js/background.js

@@ -56,7 +56,6 @@ const µBlock = (( ) => { // jshint ignore:line
         filterAuthorMode: false,
         loggerPopupType: 'popup',
         manualUpdateAssetFetchPeriod: 500,
-        popupCosmeticFilterBadgeSlow: false,
         popupFontSize: 'unset',
         requestJournalProcessPeriod: 1000,
         selfieAfter: 3,

src/js/messaging.js

@@ -387,10 +387,7 @@ const onMessage = function(request, sender, callback) {
     // Async
     switch ( request.what ) {
     case 'getHiddenElementCount':
-        const scriptlet = µb.hiddenSettings.popupCosmeticFilterBadgeSlow
+        getElementCount(request.tabId, 'elements').then(count => {
-            ? 'elements-all'
-            : 'elements';
-        getElementCount(request.tabId, scriptlet).then(count => {
             callback(count);
         });
         return;

src/js/scriptlets/dom-survey-elements-all.js

@@ -1,72 +0,0 @@
-/*******************************************************************************
-
-    uBlock Origin - a browser extension to block requests.
-    Copyright (C) 2015-present Raymond Hill
-
-    This program is free software: you can redistribute it and/or modify
-    it under the terms of the GNU General Public License as published by
-    the Free Software Foundation, either version 3 of the License, or
-    (at your option) any later version.
-
-    This program is distributed in the hope that it will be useful,
-    but WITHOUT ANY WARRANTY; without even the implied warranty of
-    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-    GNU General Public License for more details.
-
-    You should have received a copy of the GNU General Public License
-    along with this program.  If not, see {http://www.gnu.org/licenses/}.
-
-    Home: https://github.com/gorhill/uBlock
-*/
-
-'use strict';
-
-/******************************************************************************/
-
-// https://github.com/uBlockOrigin/uBlock-issues/issues/756
-//   Keep in mind CPU usage with large DOM and/or filterset.
-
-(( ) => {
-    if ( typeof vAPI !== 'object' ) { return; }
-
-    const t0 = Date.now();
-
-    if ( vAPI.domSurveyElements instanceof Object === false ) {
-        vAPI.domSurveyElements = {
-            busy: false,
-            hiddenElementCount: Number.NaN,
-            surveyTime: t0,
-        };
-    }
-    const surveyResults = vAPI.domSurveyElements;
-
-    if ( surveyResults.busy ) { return; }
-    surveyResults.busy = true;
-
-    if ( surveyResults.surveyTime < vAPI.domMutationTime ) {
-        surveyResults.hiddenElementCount = Number.NaN;
-    }
-    surveyResults.surveyTime = t0;
-
-    if ( isNaN(surveyResults.hiddenElementCount) ) {
-        surveyResults.hiddenElementCount = (( ) => {
-            if ( vAPI.domFilterer instanceof Object === false ) { return 0; }
-            const details = vAPI.domFilterer.getAllSelectors_(true);
-            if (
-                Array.isArray(details.declarative) === false ||
-                details.declarative.length === 0
-            ) {
-                return 0;
-            }
-            return document.querySelectorAll(
-                    details.declarative.map(entry => entry[0]).join(',')
-            ).length;
-        })();
-    }
-
-    surveyResults.busy = false;
-
-    // IMPORTANT: This is returned to the injector, so this MUST be
-    //            the last statement.
-    return surveyResults.hiddenElementCount;
-})();

src/js/scriptlets/dom-survey-elements.js

@@ -30,7 +30,6 @@
     if ( typeof vAPI !== 'object' ) { return; }
 
     const t0 = Date.now();
-    const tMax = t0 + 100;
 
     if ( vAPI.domSurveyElements instanceof Object === false ) {
         vAPI.domSurveyElements = {
@@ -59,48 +58,9 @@
             ) {
                 return 0;
             }
-            const selectors = details.declarative.map(entry => entry[0]);
+            return document.querySelectorAll(
-            const simple = [], complex = [];
+                    details.declarative.map(entry => entry[0]).join(',')
-            for ( const selectorStr of selectors ) {
+            ).length;
-                for ( const selector of selectorStr.split(',\n') ) {
-                    if ( /[ +>~]/.test(selector) ) {
-                        complex.push(selector);
-                    } else {
-                        simple.push(selector);
-                    }
-                }
-            }
-            const simpleStr = simple.join(',\n');
-            const complexStr = complex.join(',\n');
-            const nodeIter = document.createTreeWalker(
-                document.body,
-                NodeFilter.SHOW_ELEMENT
-            );
-            const matched = new Set();
-            let node = nodeIter.nextNode();
-            for (;;) {
-                if ( node === null ) { break; }
-                if ( Date.now() > tMax ) { return -1; }
-                if (
-                    (node.offsetParent !== null) ||
-                    (simpleStr === '' || node.matches(simpleStr) === false) &&
-                    (complexStr === '' || node.closest(complexStr) !== node)
-                ) {
-                    node = nodeIter.nextNode();
-                    continue;
-                }
-                matched.add(node);
-                if ( matched.size === 99 ) { break; }
-                // https://github.com/uBlockOrigin/uBlock-issues/issues/756#issuecomment-549079064
-                //   Skip descendants when a match is detected.
-                for (;;) {
-                    node = nodeIter.nextSibling();
-                    if ( node !== null ) { break; }
-                    node = nodeIter.parentNode();
-                    if ( node === null ) { break; }
-                }
-            }
-            return matched.size;
         })();
     }