Move 'dart:mojo.internal' into sdk_ext directory of mojo package

mojo/dart/embedder/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.
 
 # embedder specific template rules.
 import("embedder.gni")
 
 source_set("dart_controller_no_snapshot") {
   sources = [
     "$target_gen_dir/dart_embedder_patch_resources.cc",
@@ skipping 85 matching lines @@
 dart_embedder_package("dart_embedder_package_network_service") {
   package = "mojo/services/network/public/interfaces"
   destination = "mojom/mojo"
 }
 
 action_foreach("dart_embedder_package_sdk") {
   sources = [
     "//mojo/public/dart/lib/application.dart",
     "//mojo/public/dart/lib/bindings.dart",
     "//mojo/public/dart/lib/core.dart",
-    "//mojo/public/dart/lib/internal.dart",
     "//mojo/public/dart/lib/src/application.dart",
     "//mojo/public/dart/lib/src/application_connection.dart",
     "//mojo/public/dart/lib/src/buffer.dart",
     "//mojo/public/dart/lib/src/codec.dart",
     "//mojo/public/dart/lib/src/control_message.dart",
     "//mojo/public/dart/lib/src/data_pipe.dart",
     "//mojo/public/dart/lib/src/drain_data.dart",
     "//mojo/public/dart/lib/src/event_stream.dart",
     "//mojo/public/dart/lib/src/handle.dart",
-    "//mojo/public/dart/lib/src/handle_watcher.dart",
     "//mojo/public/dart/lib/src/message.dart",
     "//mojo/public/dart/lib/src/message_pipe.dart",
-    "//mojo/public/dart/lib/src/natives.dart",
     "//mojo/public/dart/lib/src/proxy.dart",
     "//mojo/public/dart/lib/src/struct.dart",
     "//mojo/public/dart/lib/src/stub.dart",
-    "//mojo/public/dart/lib/src/timer_queue.dart",
     "//mojo/public/dart/lib/src/types.dart",
+    "//mojo/public/dart/sdk_ext/internal.dart",
+    "//mojo/public/dart/sdk_ext/src/handle_watcher.dart",
+    "//mojo/public/dart/sdk_ext/src/natives.dart",
+    "//mojo/public/dart/sdk_ext/src/timer_queue.dart",
   ]
   outputs = [
     "$root_gen_dir/dart_embedder_packages/{{source_root_relative_dir}}/{{source_file_part}}",
   ]
   script = rebase_path(
           "//mojo/dart/embedder/tools/dart_rewrite_embedder_package_imports.py")
   args = [
     rebase_path("{{source}}", "", root_build_dir),
     rebase_path(
         "$root_gen_dir/dart_embedder_packages/{{source_root_relative_dir}}/{{source_file_part}}"),
@@ skipping 156 matching lines @@
 action("generate_snapshot_bin") {
   deps = [
     "//dart/runtime/bin:gen_snapshot($host_toolchain)",
     ":dart_embedder_packages",
   ]
   inputs = [
     "snapshot.dart",
     "//dart/runtime/tools/create_snapshot_bin.py",
     "//mojo/dart/embedder/builtin.dart",
     "//mojo/dart/embedder/packages.dart",
-    "//mojo/public/dart/lib/internal.dart",
     "//mojo/public/dart/lib/io.dart",
-    "//mojo/public/dart/lib/src/handle_watcher.dart",
-    "//mojo/public/dart/lib/src/natives.dart",
-    "//mojo/public/dart/lib/src/timer_queue.dart",
+    "//mojo/public/dart/sdk_ext/internal.dart",
+    "//mojo/public/dart/sdk_ext/src/handle_watcher.dart",
+    "//mojo/public/dart/sdk_ext/src/natives.dart",
+    "//mojo/public/dart/sdk_ext/src/timer_queue.dart",
   ]
   vm_isolate_snapshot = "$target_gen_dir/vm_isolate_snapshot.bin"
   isolate_snapshot = "$target_gen_dir/isolate_snapshot.bin"
   outputs = [
     vm_isolate_snapshot,
     isolate_snapshot,
   ]
 
   gen_snapshot_dir =
       get_label_info("//dart/runtime/bin:gen_snapshot($host_toolchain)",
                      "root_out_dir")
   script = "//dart/runtime/tools/create_snapshot_bin.py"
   builtin_path = rebase_path("//mojo/dart/embedder/builtin.dart")
-  internal_path = rebase_path("//mojo/public/dart/lib/internal.dart")
+  internal_path = rebase_path("//mojo/public/dart/sdk_ext/internal.dart")
   io_path = rebase_path("//mojo/public/dart/lib/io.dart")
 
   embedder_packages_path = rebase_path("//mojo/dart/embedder/packages.dart")
   embedder_package_application_path = rebase_path(
           "$root_gen_dir/dart_embedder_packages/mojo/public/dart/lib/application.dart")
   embedder_package_bindings_path = rebase_path(
           "$root_gen_dir/dart_embedder_packages/mojo/public/dart/lib/bindings.dart")
   embedder_package_core_path =
       rebase_path(
           "$root_gen_dir/dart_embedder_packages/mojo/public/dart/lib/core.dart")
@@ skipping 65 matching lines @@
     "--vm_input_bin",
     rebase_path("$target_gen_dir/vm_isolate_snapshot.bin"),
     "--input_bin",
     rebase_path("$target_gen_dir/isolate_snapshot.bin"),
     "--input_cc",
     rebase_path("//mojo/dart/embedder/snapshot.cc.tmpl"),
     "--output",
     rebase_path(output),
   ]
 }