Dart: Renames dart:mojo_blah -> mojo:blah

mojo/dart/embedder/test/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("//mojo/public/tools/bindings/mojom.gni")
 import("//testing/test.gni")
 
 action("generate_test_snapshot_bin") {
   deps = [
     "//dart/runtime/bin:gen_snapshot($host_toolchain)",
@@ skipping 35 matching lines @@
     "--executable",
     rebase_path("$gen_snapshot_dir/gen_snapshot"),
     "--package_root",
     rebase_path("$root_gen_dir"),
     "--script",
     rebase_path("test_snapshot.dart"),
     "--output_bin",
     rebase_path(output, root_build_dir),
     "--target_os",
     os,
-    "--url_mapping=dart:mojo_bindings,$bindings_path",
-    "--url_mapping=dart:mojo_builtin,$builtin_path",
-    "--url_mapping=dart:mojo_core,$core_path",
+    "--url_mapping=mojo:bindings,$bindings_path",
+    "--url_mapping=mojo:builtin,$builtin_path",
+    "--url_mapping=mojo:core,$core_path",
   ]
 }
 
 action("generate_test_snapshot_file") {
   deps = [
     ":generate_test_snapshot_bin",
   ]
   inputs = [
     "//dart/runtime/tools/create_snapshot_file.py",
     "//mojo/dart/embedder/snapshot.cc.tmpl",
@@ skipping 95 matching lines @@
     "//mojo/public/interfaces/bindings/tests:test_interfaces",
     "//testing/gtest",
   ]
 }
 
 mojom("dart_to_cpp_bindings") {
   sources = [
     "dart_to_cpp.mojom",
   ]
 }