Update observatory_sources.gni

runtime/observatory/observatory_sources.gni

 # Copyright (c) 2017, the Dart project authors. Please see the AUTHORS file
 # 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.
 
 # DO NOT EDIT. This file is generated by update_sources.py in this directory.
 
 # This file contains all dart, css, and html sources for Observatory.
 observatory_sources = [
   "lib/allocation_profile.dart",
   "lib/app.dart",
@@ skipping 74 matching lines @@
   "lib/src/elements/isolate_ref.dart",
   "lib/src/elements/isolate_view.dart",
   "lib/src/elements/json_view.dart",
   "lib/src/elements/library_ref.dart",
   "lib/src/elements/library_view.dart",
   "lib/src/elements/local_var_descriptors_ref.dart",
   "lib/src/elements/logging.dart",
   "lib/src/elements/logging_list.dart",
   "lib/src/elements/megamorphiccache_ref.dart",
   "lib/src/elements/megamorphiccache_view.dart",
+  "lib/src/elements/memory/allocations.dart",
   "lib/src/elements/memory/dashboard.dart",
   "lib/src/elements/memory/graph.dart",
   "lib/src/elements/memory/profile.dart",
+  "lib/src/elements/memory/snapshot.dart",
   "lib/src/elements/metric/details.dart",
   "lib/src/elements/metric/graph.dart",
   "lib/src/elements/metrics.dart",
   "lib/src/elements/native_memory_profiler.dart",
   "lib/src/elements/nav/class_menu.dart",
   "lib/src/elements/nav/isolate_menu.dart",
   "lib/src/elements/nav/library_menu.dart",
   "lib/src/elements/nav/menu_item.dart",
   "lib/src/elements/nav/notify.dart",
   "lib/src/elements/nav/notify_event.dart",
@@ skipping 167 matching lines @@
   "lib/tracer.dart",
   "lib/utils.dart",
   "web/favicon.ico",
   "web/index.html",
   "web/main.dart",
   "web/third_party/trace_viewer_full.html",
   "web/timeline.html",
   "web/timeline.js",
   "web/timeline_message_handler.js",
 ]