Allow embedder to set promise internal field count

BUILD.gn

 # Copyright 2014 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 import("//build/config/android/config.gni")
 import("//build/config/arm.gni")
 import("//build/config/dcheck_always_on.gni")
 import("//build/config/host_byteorder.gni")
 import("//build/config/mips.gni")
 import("//build/config/sanitizers/sanitizers.gni")
@@ skipping 27 matching lines @@
 
   # Enable compiler warnings when using V8_DEPRECATE_SOON apis.
   v8_imminent_deprecation_warnings = false
 
   # Embeds the given script into the snapshot.
   v8_embed_script = ""
 
   # Sets -dENABLE_DISASSEMBLER.
   v8_enable_disassembler = ""
 
+  # Sets the number of internal fields on promise objects.
+  v8_promise_internal_field_count = ""

[jochen (gone - plz use gerrit), 2017/05/23 11:19:49]

that should be a number, no?

[mattloring, 2017/05/23 16:54:42]

Done.

+
   # Sets -dENABLE_GDB_JIT_INTERFACE.
   v8_enable_gdbjit = ""
 
   # Sets -dENABLE_VTUNE_JIT_INTERFACE.
   v8_enable_vtunejit = false
 
   # Sets -dENABLE_HANDLE_ZAPPING.
   v8_enable_handle_zapping = true
 
   # Enable slow dchecks.
@@ skipping 141 matching lines @@
 }
 
 config("features") {
   visibility = [ ":*" ]  # Only targets in this file can depend on this.
 
   defines = []
 
   if (v8_enable_disassembler) {
     defines += [ "ENABLE_DISASSEMBLER" ]
   }
+  if (v8_promise_internal_field_count) {
+    defines += [ "V8_PROMISE_INTERNAL_FIELD_COUNT" ]

[jochen (gone - plz use gerrit), 2017/05/23 11:19:49]

and that should be
V8_PROMISE_INTERNAL_FIELD_COUNT=${v8_promise_internal_field_count}

[mattloring, 2017/05/23 16:54:43]

Done.

+  }
   if (v8_enable_future) {
     defines += [ "V8_ENABLE_FUTURE" ]
   }
   if (v8_disable_turbo) {
     defines += [ "V8_DISABLE_TURBO" ]
   }
   if (v8_enable_gdbjit) {
     defines += [ "ENABLE_GDB_JIT_INTERFACE" ]
   }
   if (v8_enable_vtunejit) {
@@ skipping 3049 matching lines @@
   ]
 
   configs = [
     ":external_config",
     ":internal_config_base",
   ]
 }
 
 v8_fuzzer("wasm_compile_fuzzer") {
 }