Cleanup randomFill. NFC (#23260)

Under node we can rely on `randomFillSync` always being available since
its been around since v9.0.0:


https://nodejs.org/api/crypto.html#cryptorandomfillsyncbuffer-offset-size

Also, remove the return value from this function since it always fills
the entire buffer.

https://caniuse.com/getrandomvalues

Author: sbc100

src/closure-externs/node-externs.js

@@ -137,3 +137,5 @@ path.isAbsolute;
  * @type {Object.<string,*>}
  */
 path.posix;
+
+crypto.randomFillSync;

src/library_fs.js

@@ -1411,7 +1411,8 @@ FS.staticInit();
       var randomBuffer = new Uint8Array(1024), randomLeft = 0;
       var randomByte = () => {
         if (randomLeft === 0) {
-          randomLeft = randomFill(randomBuffer).byteLength;
+          randomFill(randomBuffer);
+          randomLeft = randomBuffer.byteLength;
         }
         return randomBuffer[--randomLeft];
       };

src/library_wasi.js

@@ -561,53 +561,35 @@ var WasiLibrary = {
   // random.h
 
   $initRandomFill: () => {
-    if (typeof crypto == 'object' && typeof crypto['getRandomValues'] == 'function') {
-      // for modern web browsers
+    if (typeof crypto == 'object' && typeof crypto.getRandomValues == 'function') {
 #if SHARED_MEMORY
       // like with most Web APIs, we can't use Web Crypto API directly on shared memory,
       // so we need to create an intermediate buffer and copy it to the destination
-      return (view) => (
-        view.set(crypto.getRandomValues(new Uint8Array(view.byteLength))),
-        // Return the original view to match modern native implementations.
-        view
-      );
+      return (view) => view.set(crypto.getRandomValues(new Uint8Array(view.byteLength)));
 #else
       return (view) => crypto.getRandomValues(view);
 #endif
-    } else
+    }
+
 #if ENVIRONMENT_MAY_BE_NODE
     if (ENVIRONMENT_IS_NODE) {
-      // for nodejs with or without crypto support included
-      try {
-        var crypto_module = require('crypto');
-        var randomFillSync = crypto_module['randomFillSync'];
-        if (randomFillSync) {
-          // nodejs with LTS crypto support
-          return (view) => crypto_module['randomFillSync'](view);
-        }
-        // very old nodejs with the original crypto API
-        return (view) => (
-          view.set(crypto_module['randomBytes'](view.byteLength)),
-          // Return the original view to match modern native implementations.
-          view
-        );
-      } catch (e) {
-        // nodejs doesn't have crypto support
-      }
+      return (view) => require('crypto').randomFillSync(view);
     }
 #endif // ENVIRONMENT_MAY_BE_NODE
-    // we couldn't find a proper implementation, as Math.random() is not suitable for /dev/random, see emscripten-core/emscripten/pull/7096
+
+    // we couldn't find a proper implementation, as Math.random() is not
+    // suitable for /dev/random, see emscripten-core/emscripten/pull/7096
 #if ASSERTIONS
-    abort('no cryptographic support found for randomDevice. consider polyfilling it if you want to use something insecure like Math.random(), e.g. put this in a --pre-js: var crypto = { getRandomValues: (array) => { for (var i = 0; i < array.length; i++) array[i] = (Math.random()*256)|0 } };');
+    abort('no cryptographic support found for random function. consider polyfilling it if you want to use something insecure like Math.random(), e.g. put this in a --pre-js: var crypto = { getRandomValues: (array) => { for (var i = 0; i < array.length; i++) array[i] = (Math.random()*256)|0 } };');
 #else
-    abort('initRandomDevice');
+    abort();
 #endif
   },
 
   $randomFill__deps: ['$initRandomFill'],
   $randomFill: (view) => {
     // Lazily init on the first invocation.
-    return (randomFill = initRandomFill())(view);
+    (randomFill = initRandomFill())(view);
   },
 
   random_get__proxy: 'none',

test/other/codesize/test_codesize_cxx_ctors1.gzsize

@@ -1 +1 @@
-8405
+8365

test/other/codesize/test_codesize_cxx_ctors1.jssize

@@ -1 +1 @@
-20468
+20373

test/other/codesize/test_codesize_cxx_ctors1.size

@@ -1 +1 @@
-128894
+128914

test/other/codesize/test_codesize_cxx_ctors2.gzsize

@@ -1 +1 @@
-8390
+8347

test/other/codesize/test_codesize_cxx_ctors2.jssize

@@ -1 +1 @@
-20436
+20341

test/other/codesize/test_codesize_cxx_ctors2.size

@@ -1 +1 @@
-128343
+128363

test/other/codesize/test_codesize_cxx_except.gzsize

@@ -1 +1 @@
-9412
+9369