Injects user styles and content scripts in `about:blank` frames

Related issues:
- https://github.com/uBlockOrigin/uBlock-issues/issues/688
- https://github.com/uBlockOrigin/uBlock-issues/issues/1164

`match_about_blank` is now used for content scripts and
user styles.

platform/chromium/manifest.json

@@ -39,8 +39,9 @@
         "/js/vapi-client.js",
         "/js/contentscript.js"
       ],
-      "run_at": "document_start",
-      "all_frames": true
+      "all_frames": true,
+      "match_about_blank": true,
+      "run_at": "document_start"
     },
     {
       "matches": [

platform/firefox/manifest.json

@@ -49,8 +49,9 @@
         "/js/vapi-client.js",
         "/js/contentscript.js"
       ],
-      "run_at": "document_start",
-      "all_frames": true
+      "all_frames": true,
+      "match_about_blank": true,
+      "run_at": "document_start"
     },
     {
       "matches": [

platform/opera/manifest.json

@@ -30,16 +30,17 @@
   },
   "content_scripts": [
     {
-      "all_frames": true,
+      "matches": [
+        "http://*/*",
+        "https://*/*"
+      ],
       "js": [
         "js/vapi.js",
         "js/vapi-client.js",
         "js/contentscript.js"
       ],
-      "matches": [
-        "http://*/*",
-        "https://*/*"
-      ],
+      "all_frames": true,
+      "match_about_blank": true,
       "run_at": "document_start"
     },
     {

platform/thunderbird/manifest.json

@@ -30,8 +30,9 @@
         "/js/vapi-client.js",
         "/js/contentscript.js"
       ],
-      "run_at": "document_start",
-      "all_frames": true
+      "all_frames": true,
+      "match_about_blank": true,
+      "run_at": "document_start"
     },
     {
       "matches": [

src/js/contentscript.js

@@ -1053,27 +1053,14 @@ vAPI.domCollapser = (function() {
         attributeFilter: [ 'src' ]
     };
 
-    // The injected scriptlets are those which were injected in the current
-    // document, from within `bootstrapPhase1`, and which scriptlets are
-    // selectively looked-up from:
-    // https://github.com/uBlockOrigin/uAssets/blob/master/filters/resources.txt
-    const primeLocalIFrame = function(iframe) {
-        if ( vAPI.injectedScripts ) {
-            vAPI.injectScriptlet(iframe.contentDocument, vAPI.injectedScripts);
-        }
-    };
-
     // https://github.com/gorhill/uBlock/issues/162
-    // Be prepared to deal with possible change of src attribute.
+    //   Be prepared to deal with possible change of src attribute.
     const addIFrame = function(iframe, dontObserve) {
         if ( dontObserve !== true ) {
             iframeSourceObserver.observe(iframe, iframeSourceObserverOptions);
         }
         const src = iframe.src;
-        if ( src === '' || typeof src !== 'string' ) {
-            primeLocalIFrame(iframe);
-            return;
-        }
+        if ( typeof src !== 'string' || src === '' ) { return; }
         if ( src.startsWith('http') === false ) { return; }
         toFilter.push({ type: 'sub_frame', url: iframe.src });
         add(iframe);

src/js/cosmetic-filtering.js

@@ -959,7 +959,8 @@ FilterContainer.prototype.retrieveGenericSelectors = function(request) {
             code: out.injected + '\n{display:none!important;}',
             cssOrigin: 'user',
             frameId: request.frameId,
-            runAt: 'document_start'
+            matchAboutBlank: true,
+            runAt: 'document_start',
         });
     }
 
@@ -1151,7 +1152,8 @@ FilterContainer.prototype.retrieveSpecificSelectors = function(
             code: '',
             cssOrigin: 'user',
             frameId: request.frameId,
-            runAt: 'document_start'
+            matchAboutBlank: true,
+            runAt: 'document_start',
         };
         if ( out.injectedHideFilters.length !== 0 ) {
             details.code = out.injectedHideFilters + '\n{display:none!important;}';