GN: Don't depend on dart_bootstrap if there is a usable prebuilt sdk

utils/application_snapshot.gni

Index: utils/application_snapshot.gni
diff --git a/utils/invoke_dart.gni b/utils/application_snapshot.gni
similarity index 57%
rename from utils/invoke_dart.gni
rename to utils/application_snapshot.gni
index bc4747a0bde957914438977b30e8b33ede16e943..0f36737bbd40c5d6942d7d54808419d2ed723c13 100644
--- a/utils/invoke_dart.gni
+++ b/utils/application_snapshot.gni
@@ -2,49 +2,9 @@
 # for details. All rights reserved. Use of this source code is governed by a
 # BSD-style license that can be found in the LICENSE file.
 
-_dart_root = rebase_path("..")
-
-if (defined(is_win) && is_win) {
-  dart_executable_suffix = ".exe"
-} else {
-  dart_executable_suffix = ""
-}
-
-template("invoke_dart") {
-  assert(defined(invoker.outputs), "invoke_dart must specify outputs")
-  extra_deps = []
-  if (defined(invoker.deps)) {
-    extra_deps += invoker.deps
-  }
-
-  extra_inputs = []
-  if (defined(invoker.inputs)) {
-    extra_inputs += invoker.inputs
-  }
-
-  extra_args = []
-  if (defined(invoker.args)) {
-    extra_args += invoker.args
-  }
-
-  action(target_name) {
-    relative_dart_root = rebase_path(_dart_root, ".")
-    deps =
-        extra_deps + [ "$relative_dart_root/runtime/bin:dart($host_toolchain)" ]
-
-    dart_out_dir =
-        get_label_info("$relative_dart_root/runtime/bin:dart($host_toolchain)",
-                       "root_out_dir")
-    dart = rebase_path("$dart_out_dir/dart$dart_executable_suffix")
+import("//build/compiled_action.gni")
 
-    inputs = [ dart ] + extra_inputs
-
-    outputs = invoker.outputs
-
-    script = "$_dart_root/tools/dart_for_gn.py"
-    args = [ dart ] + extra_args
-  }
-}
+_dart_root = rebase_path("..")
 
 template("application_snapshot") {
   assert(defined(invoker.main_dart), "Must specify 'main_dart'")
@@ -63,7 +23,8 @@ template("application_snapshot") {
   if (defined(invoker.inputs)) {
     extra_inputs += invoker.inputs
   }
-  invoke_dart(target_name) {
+  compiled_action(target_name) {
+    tool = get_path_info("$_dart_root/runtime/bin:dart", "abspath")
     deps = extra_deps + [ "$_dart_root/pkg:pkg_files_stamp" ]
 
     inputs = extra_inputs + [