Dynamically reload 3p css when noop-ing "3rd-party" cell

This should improve usability of uBO's hard-mode
and "relax blocking mode" operations. This is the
new default behavior.

The previous behavior of forcing a reload of the
page can be re-enabled by simply setting the `3p`
bit of the advanced setting `blockingProfiles`
to 1.

Author: gorhill

src/js/background.js

@@ -43,7 +43,7 @@ const µBlock = (( ) => { // jshint ignore:line
         autoUpdateDelayAfterLaunch: 180,
         autoUpdatePeriod: 7,
         benchmarkDatasetURL: 'unset',
-        blockingProfiles: '11111/#F00 11011/#C0F 11001/#00F 00001',
+        blockingProfiles: '11111/#F00 11010/#C0F 11001/#00F 00001',
         cacheStorageAPI: 'unset',
         cacheStorageCompression: true,
         cacheControlForFirefox1376932: 'no-cache, no-store, must-revalidate',

src/js/commands.js

@@ -88,6 +88,8 @@ const relaxBlockingMode = (( ) => {
         // TODO: Reset to original blocking profile?
         if ( newProfileBits === undefined ) { return; }
 
+        const noReload = (newProfileBits & 0b00000001) === 0;
+
         if (
             (curProfileBits & 0b00000010) !== 0 &&
             (newProfileBits & 0b00000010) === 0
@@ -104,6 +106,7 @@ const relaxBlockingMode = (( ) => {
                 (newProfileBits & 0b00000100) === 0
             ) {
                 µb.toggleFirewallRule({
+                    tabId: noReload ? tab.id : undefined,
                     srcHostname: hn,
                     desHostname: '*',
                     requestType: '3p',
@@ -135,7 +138,7 @@ const relaxBlockingMode = (( ) => {
         }
 
         // Reload the target tab?
-        if ( (newProfileBits & 0b00000001) === 0 ) { return; }
+        if ( noReload ) { return; }
 
         // Reload: use a timer to coalesce bursts of reload commands.
         let timer = reloadTimers.get(tab.id);

src/js/scriptlets/load-3p-css.js

@@ -0,0 +1,70 @@
+/*******************************************************************************
+
+    uBlock Origin - a browser extension to block requests.
+    Copyright (C) 2020-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';
+
+/******************************************************************************/
+
+(( ) => {
+    if ( typeof vAPI !== 'object' ) { return; }
+
+    if ( vAPI.load3rdPartyCSS ) { return; }
+    vAPI.load3rdPartyCSS = true;
+
+    const links = document.querySelectorAll('link[rel="stylesheet"]');
+    if ( links.length === 0 ) { return; }
+
+    const toLoadMaybe = new Map(Array.from(links).map(a => [ a.href, a ]));
+
+    for ( const sheet of Array.from(document.styleSheets) ) {
+        let loaded = false;
+        try {
+            loaded = sheet.rules.length !== 0;
+        } catch(ex) {
+        }
+        if ( loaded ) { continue; }
+        const link = toLoadMaybe.get(sheet.href);
+        if ( link === undefined ) { continue; }
+        toLoadMaybe.delete(sheet.href);
+        const clone = link.cloneNode(true);
+        link.replaceWith(clone);
+    }
+})();
+
+
+
+
+
+
+
+
+/*******************************************************************************
+
+    DO NOT:
+    - Remove the following code
+    - Add code beyond the following code
+    Reason:
+    - https://github.com/gorhill/uBlock/pull/3721
+    - uBO never uses the return value from injected content scripts
+
+**/
+
+void 0;

src/js/ublock.js

@@ -509,9 +509,19 @@ const matchBucket = function(url, hostname, bucket, start) {
     // https://github.com/chrisaljoudi/uBlock/issues/420
     this.cosmeticFilteringEngine.removeFromSelectorCache(srcHostname, 'net');
 
+    if ( details.tabId === undefined ) { return; }
+
     if ( requestType.startsWith('3p') ) {
         this.updateToolbarIcon(details.tabId, 0b100);
     }
+
+    if ( requestType === '3p' && action === 3 ) {
+        vAPI.tabs.executeScript(details.tabId, {
+            file: '/js/scriptlets/load-3p-css.js',
+            allFrames: true,
+            runAt: 'document_idle',
+        });
+    }
 };
 
 /******************************************************************************/