[gn] Automatically derive build configs in test runner.

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 599 matching lines @@
 
   if (v8_use_external_startup_data) {
     outputs += [ "$root_out_dir/snapshot_blob.bin" ]
     args += [
       "--startup_blob",
       rebase_path("$root_out_dir/snapshot_blob.bin", root_build_dir),
     ]
   }
 }
 
+action("v8_dump_build_config") {
+  script = "tools/testrunner/utils/dump_build_config.py"
+  outputs = [ "$root_out_dir/v8_build_config.json" ]
+  args = [
+    rebase_path("$root_out_dir/v8_build_config.json", root_build_dir),
+    "dcheck_always_on=$dcheck_always_on",
+    "is_asan=$is_asan",
+    "is_cfi=$is_cfi",
+    "is_component_build=$is_component_build",
+    "is_debug=$is_debug",
+    "is_msan=$is_msan",
+    "is_tsan=$is_tsan",
+    "target_cpu=\"$target_cpu\"",
+    "v8_enable_i18n_support=$v8_enable_i18n_support",
+    "v8_target_cpu=\"$v8_target_cpu\"",
+    "v8_use_snapshot=$v8_use_snapshot",
+  ]  
+}
+
+
 ###############################################################################
 # Source Sets (aka static libraries)
 #
 
 source_set("v8_maybe_snapshot") {
   if (v8_use_snapshot && v8_use_external_startup_data) {
     public_deps = [
       ":v8_external_snapshot",
     ]
   } else if (v8_use_snapshot) {
@@ skipping 1461 matching lines @@
     deps += [ ":d8_run" ]
   }
 }
 
 if (is_component_build) {
   v8_component("v8") {
     sources = [
       "src/v8dll-main.cc",
     ]
 
+    deps = [ ":v8_dump_build_config" ]
+
     public_deps = [
       ":v8_base",
       ":v8_maybe_snapshot",
     ]
 
     configs = [ ":internal_config" ]
 
     public_configs = [ ":external_config" ]
   }
 } else {
   group("v8") {
+    deps = [ ":v8_dump_build_config" ]
+
     public_deps = [
       ":v8_base",
       ":v8_maybe_snapshot",
     ]
     public_configs = [ ":external_config" ]
   }
 }
 
 v8_executable("d8") {
   sources = [
@@ skipping 225 matching lines @@
 
   deps = [
     ":fuzzer_support",
   ]
 
   configs = [ ":internal_config" ]
 }
 
 v8_fuzzer("wasm_asmjs_fuzzer") {
 }