[gn] Add swarming support

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/mips.gni")
 import("//build/config/sanitizers/sanitizers.gni")
 
 if (is_android) {
   import("//build/config/android/rules.gni")
 }
 
 import("gni/v8.gni")
+import("gni/isolate.gni")
 import("//build_overrides/v8.gni")
 
 import("snapshot_toolchain.gni")
 
 declare_args() {
-  # Enable the snapshot feature, for fast context creation.
-  # http://v8project.blogspot.com/2015/09/custom-startup-snapshots.html
-  v8_use_snapshot = true
-
-  # Use external files for startup data blobs:
-  # the JS builtins sources and the start snapshot.
-  v8_use_external_startup_data = !is_ios
-
   # Sets -DVERIFY_HEAP.
   v8_enable_verify_heap = false
 
   # Enable compiler warnings when using V8_DEPRECATED apis.
   v8_deprecation_warnings = false
 
   # Enable compiler warnings when using V8_DEPRECATE_SOON apis.
   v8_imminent_deprecation_warnings = false
 
   # Sets -dENABLE_DISASSEMBLER.
@@ skipping 2103 matching lines @@
   }
 
   if (!is_component_build) {
     sources += [ "$target_gen_dir/d8-js.cc" ]
   }
   if (v8_enable_i18n_support) {
     deps += [ "//third_party/icu" ]
   }
 }
 
+v8_isolate_run("d8") {

[Michael Achenbach, 2016/06/02 14:23:57]

This ports https://cs.chromium.org/chromium/src/v8/src/d8.gyp?l=142

Only d8 for now to test this on the staging bot. Others in follow up CLs.

+  deps = [
+    ":d8",
+  ]
+
+  isolate = "//src/d8.isolate"
+}
+
 if (want_v8_shell) {
   executable("v8_shell") {
     sources = [
       "samples/shell.cc",
     ]
 
     configs -= [ "//build/config/compiler:chromium_code" ]
     configs += [ "//build/config/compiler:no_chromium_code" ]
     configs += [
       # Note: don't use :internal_config here because this target will get
@@ skipping 69 matching lines @@
   sources = [
     "test/fuzzer/wasm-asmjs.cc",
   ]
 
   deps = [
     ":fuzzer_support",
   ]
 
   configs = [ ":internal_config" ]
 }