[v8-extras] Remove `simpleBind`

The `simpleBind` function exposed by V8 Extras was initially added to
work around the terrible performance of `Function.prototype.bind` at
the time. Nowadays `Function.prototype.bind` is significantly faster
and fully optimized by TurboFan, however, so there’s no need for the
`simpleBind` helper anymore.

Bug: chromium:807522
Change-Id: I1a0456e2aa34f92a3c9a0234a812b660f969d016
Reviewed-on: https://chromium-review.googlesource.com/903164Reviewed-by: Benedikt Meurer <bmeurer@chromium.org>
Commit-Queue: Mathias Bynens <mathias@chromium.org>
Cr-Commit-Position: refs/heads/master@{#51108}

src/js/prologue.js

@@ -177,13 +177,7 @@ extrasUtils.createPrivateSymbol = function createPrivateSymbol(name) {
 //
 // Technically they could all be derived from combinations of
 // Function.prototype.{bind,call,apply} but that introduces lots of layers of
-// indirection and slowness given how un-optimized bind is.
-
-extrasUtils.simpleBind = function simpleBind(func, thisArg) {
-  return function(...args) {
-    return %reflect_apply(func, thisArg, args);
-  };
-};
+// indirection.
 
 extrasUtils.uncurryThis = function uncurryThis(func) {
   return function(thisArg, ...args) {

test/cctest/test-extra.js

@@ -23,7 +23,7 @@
 
   // Exercise all of the extras utils:
   // - v8.createPrivateSymbol
-  // - v8.simpleBind, v8.uncurryThis
+  // - v8.uncurryThis
   // - v8.InternalPackedArray
   // - v8.createPromise, v8.resolvePromise, v8.rejectPromise
 
@@ -35,7 +35,7 @@
   const apply = v8.uncurryThis(Function.prototype.apply);
 
   const Promise = global.Promise;
-  const Promise_resolve = v8.simpleBind(Promise.resolve, Promise);
+  const Promise_resolve = Promise.resolve.bind(Promise);
 
   const arrayToTest = new v8.InternalPackedArray();
   arrayToTest.push(1);