Add isPromise V8 extras util

This is used by streams in
https://streams.spec.whatwg.org/commit-snapshots/1375e266b2fe8246bd95cb9d8a49876ba9359dc9/#rs-pipe-through

This also fixes an omission in a6e635d6
that did not properly update the
%OptimizeObjectForAddingMultipleProperties call in prologue.js.

BUG=chromium:668951
R=gsathya@chromium.org,littledan@chromium.org

Review-Url: https://codereview.chromium.org/2796243002
Cr-Commit-Position: refs/heads/master@{#44442}

src/bootstrapper.cc

@@ -4214,6 +4214,8 @@ bool Genesis::InstallNatives(GlobalContextType context_type) {
                   factory()->NewStringFromAsciiChecked("createPromise"));
   InstallFunction(extras_utils, isolate()->promise_resolve(),
                   factory()->NewStringFromAsciiChecked("resolvePromise"));
+  InstallFunction(extras_utils, isolate()->is_promise(),
+                  factory()->NewStringFromAsciiChecked("isPromise"));
 
   int builtin_index = Natives::GetDebuggerCount();
   // Only run prologue.js and runtime.js at this point.

src/js/prologue.js

@@ -168,7 +168,7 @@ utils.PostNatives = PostNatives;
 
 // -----------------------------------------------------------------------
 
-%OptimizeObjectForAddingMultipleProperties(extrasUtils, 7);
+%OptimizeObjectForAddingMultipleProperties(extrasUtils, 11);
 
 extrasUtils.logStackTrace = function logStackTrace() {
   %DebugTrace();

test/cctest/test-api.cc

@@ -25492,6 +25492,17 @@ TEST(ExtrasUtilsObject) {
                             .As<v8::String>();
   String::Utf8Value promise_states_string(promise_states);
   CHECK_EQ(0, strcmp(*promise_states_string, "pending fulfilled rejected"));
+
+  auto promise_is_promise = result->Get(env.local(), v8_str("promiseIsPromise"))
+                                .ToLocalChecked()
+                                .As<v8::Boolean>();
+  CHECK_EQ(true, promise_is_promise->Value());
+
+  auto thenable_is_promise =
+      result->Get(env.local(), v8_str("thenableIsPromise"))
+          .ToLocalChecked()
+          .As<v8::Boolean>();
+  CHECK_EQ(false, thenable_is_promise->Value());
 }
 
 

test/cctest/test-extra.js

@@ -93,7 +93,9 @@
       fulfilledPromise2, // should be fulfilled with 2
       rejectedPromise, // should be rejected with 3
       rejectedButHandledPromise, // should be rejected but have a handler
-      promiseStates // should be the string "pending fulfilled rejected"
+      promiseStates, // should be the string "pending fulfilled rejected"
+      promiseIsPromise: v8.isPromise(fulfilledPromise), // should be true
+      thenableIsPromise: v8.isPromise({ then() { } })  // should be false
     };
   };
 })