Introduce mkgrokdump to update tools/v8heapconst.py.

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/mips.gni")
 import("//build/config/sanitizers/sanitizers.gni")
 
@@ skipping 2595 matching lines @@
       ":v8_builtins_setup",
       ":v8_libbase",
       ":v8_libplatform",
       ":v8_nosnapshot",
       "//build/config/sanitizers:deps",
       "//build/win:default_exe_manifest",
     ]
   }
 }
 
+v8_executable("mkgrokdump") {
+  # mkgrokdump is used to create tools/v8heapconst.py.
+  visibility = [ ":*" ]  # Only targets in this file can depend on this.
+
+  sources = [
+    "tools/mkgrokdump.cc",
+  ]
+
+  configs = [
+    ":external_config",
+    ":internal_config",
+  ]
+
+  deps = [
+    ":v8",
+    ":v8_libbase",
+    ":v8_libplatform",
+    "//build/config/sanitizers:deps",
+    "//build/win:default_exe_manifest",
+  ]
+}
+
 ###############################################################################
 # Public targets
 #
 
 want_v8_shell =
     (current_toolchain == host_toolchain && v8_toolset_for_shell == "host") ||
     (current_toolchain == v8_snapshot_toolchain &&
      v8_toolset_for_shell == "host") ||
     (current_toolchain != host_toolchain && v8_toolset_for_shell == "target")
 
 group("gn_all") {
   testonly = true
 
   deps = [
     ":d8",
+    ":mkgrokdump",
     ":v8_fuzzers",
     ":v8_hello_world",
     ":v8_parser_shell",
     ":v8_sample_process",
     "test:gn_all",
     "tools:gn_all",
   ]
 
   if (want_v8_shell) {
     deps += [ ":v8_shell" ]
@@ skipping 552 matching lines @@
   ]
 
   configs = [
     ":external_config",
     ":internal_config_base",
   ]
 }
 
 v8_fuzzer("wasm_compile_fuzzer") {
 }