add new advanced setting to disable use of WASM for dev purpose

src/js/background.js

@@ -44,8 +44,9 @@ const µBlock = (function() { // jshint ignore:line
         autoUpdatePeriod: 7,
         benchmarkingPane: false,
         cacheStorageCompression: true,
-        debugScriptlets: false,
         cacheControlForFirefox1376932: 'no-cache, no-store, must-revalidate',
+        debugScriptlets: false,
+        disableWebAssembly: false,
         ignoreRedirectFilters: false,
         ignoreScriptInjectFilters: false,
         manualUpdateAssetFetchPeriod: 500,

src/js/hntrie.js

@@ -467,6 +467,15 @@ const hnTrieManager = {
         return;
     }
 
+    // Soft-dependency on µBlock's advanced settings so that the code here can
+    // be used outside of uBO (i.e. tests, benchmarks)
+    if (
+        typeof µBlock === 'object' &&
+        µBlock.hiddenSettings.disableWebAssembly === true
+    ) {
+        return;
+    }
+
     // The wasm module will work only if CPU is natively little-endian,
     // as we use native uint32 array in our trie-creation js code.
     const uint32s = new Uint32Array(1);

src/js/lz4.js

@@ -52,7 +52,11 @@ let init = function() {
         return Promise.resolve(lz4CodecInstance);
     }
     if ( pendingInitialization === undefined ) {
-        pendingInitialization = lz4BlockCodec.createInstance()
+        let flavor;
+        if ( µBlock.hiddenSettings.disableWebAssembly === true ) {
+            flavor = 'js';
+        }
+        pendingInitialization = lz4BlockCodec.createInstance(flavor)
             .then(instance => {
                 lz4CodecInstance = instance;
                 pendingInitialization = undefined;

src/js/storage.js

@@ -186,6 +186,7 @@
     vAPI.localStorage.setItem(
         'immediateHiddenSettings',
         JSON.stringify({
+               disableWebAssembly: this.hiddenSettings.disableWebAssembly,
             suspendTabsUntilReady: this.hiddenSettings.suspendTabsUntilReady,
             userResourcesLocation: this.hiddenSettings.userResourcesLocation
         })