Save magic compiled/selfie format values in cache storage

Related issue:
- https://bugzilla.mozilla.org/show_bug.cgi?id=1588916

Due to browser behavior changes during development,
uBO can end up using obsolete cached compiled filter
lists or selfie.

Saving magic format values in the cache storage
itself ensure uBO will properly detect actually
obsolete compiled lists/selfie.

src/js/start.js

@@ -170,9 +170,10 @@ const onUserSettingsReady = function(fetched) {
 
 /******************************************************************************/
 
-// Housekeeping, as per system setting changes
+// https://bugzilla.mozilla.org/show_bug.cgi?id=1588916
+//   Save magic format numbers into the cache storage itself.
 
-const onSystemSettingsReady = function(fetched) {
+const onCacheSettingsReady = function(fetched) {
     if ( fetched.compiledMagic !== µb.systemSettings.compiledMagic ) {
         µb.assets.remove(/^compiled\//);
         µb.compiledFormatChanged = true;
@@ -182,9 +183,8 @@ const onSystemSettingsReady = function(fetched) {
         µb.selfieIsInvalid = true;
     }
     if ( µb.selfieIsInvalid ) {
-        fetched.selfie = null;
         µb.selfieManager.destroy();
-        vAPI.storage.set(µb.systemSettings);
+        µb.cacheStorage.set(µb.systemSettings);
     }
 };
 
@@ -199,7 +199,6 @@ const onFirstFetchReady = function(fetched) {
     }
 
     // Order is important -- do not change:
-    onSystemSettingsReady(fetched);
     fromFetch(µb.localSettings, fetched);
     onUserSettingsReady(fetched);
     fromFetch(µb.restoreBackupSettings, fetched);
@@ -228,7 +227,6 @@ const fromFetch = function(to, fetched) {
 const createDefaultProps = function() {
     const fetchableProps = {
         'commandShortcuts': [],
-        'compiledMagic': 0,
         'dynamicFilteringString': [
             'behind-the-scene * * noop',
             'behind-the-scene * image noop',
@@ -247,7 +245,6 @@ const createDefaultProps = function() {
         'lastBackupFile': '',
         'lastBackupTime': 0,
         'netWhitelist': µb.netWhitelistDefault,
-        'selfieMagic': 0,
         'version': '0.0.0.0'
     };
     toFetch(µb.localSettings, fetchableProps);
@@ -275,6 +272,12 @@ try {
         µb.loadSelectedFilterLists().then(( ) => {
             log.info(`List selection ready ${Date.now()-vAPI.T0} ms after launch`);
         }),
+        µb.cacheStorage.get(
+            { compiledMagic: 0, selfieMagic: 0 }
+        ).then(fetched => {
+            log.info(`Cache magic numbers ready ${Date.now()-vAPI.T0} ms after launch`);
+            onCacheSettingsReady(fetched);
+        }),
         vAPI.storage.get(createDefaultProps()).then(fetched => {
             log.info(`First fetch ready ${Date.now()-vAPI.T0} ms after launch`);
             onFirstFetchReady(fetched);