Add Observatory support for UnlinkedCall, SingleTargetCache and SubtypeTestCache.

runtime/observatory/observatory_sources.gypi

Index: runtime/observatory/observatory_sources.gypi
diff --git a/runtime/observatory/observatory_sources.gypi b/runtime/observatory/observatory_sources.gypi
index a83a34cefabff1a74bef3471a63c202263bfa484..f4dc80c37d2f8fb1592c425f83422ffdee545b9a 100644
--- a/runtime/observatory/observatory_sources.gypi
+++ b/runtime/observatory/observatory_sources.gypi
@@ -121,15 +121,21 @@
     'lib/src/elements/script_view.dart',
     'lib/src/elements/sentinel_value.dart',
     'lib/src/elements/sentinel_view.dart',
+    'lib/src/elements/singletargetcache_ref.dart',
+    'lib/src/elements/singletargetcache_view.dart',
     'lib/src/elements/source_inset.dart',
     'lib/src/elements/source_link.dart',
     'lib/src/elements/stack_trace_tree_config.dart',
     'lib/src/elements/strongly_reachable_instances.dart',
+    'lib/src/elements/subtypetestcache_ref.dart',
+    'lib/src/elements/subtypetestcache_view.dart',
     'lib/src/elements/timeline_page.dart',
     'lib/src/elements/token_stream_ref.dart',
     'lib/src/elements/top_retaining_instances.dart',
     'lib/src/elements/type_arguments_ref.dart',
     'lib/src/elements/unknown_ref.dart',
+    'lib/src/elements/unlinkedcall_ref.dart',
+    'lib/src/elements/unlinkedcall_view.dart',
     'lib/src/elements/view_footer.dart',
     'lib/src/elements/vm_connect.dart',
     'lib/src/elements/vm_connect_target.dart',
@@ -171,13 +177,16 @@
     'lib/src/models/objects/sample_profile.dart',
     'lib/src/models/objects/script.dart',
     'lib/src/models/objects/sentinel.dart',
+    'lib/src/models/objects/single_target_cache.dart',
     'lib/src/models/objects/source_location.dart',
+    'lib/src/models/objects/subtype_test_cache.dart',
     'lib/src/models/objects/target.dart',
     'lib/src/models/objects/thread.dart',
     'lib/src/models/objects/timeline_event.dart',
     'lib/src/models/objects/token_stream.dart',
     'lib/src/models/objects/type_arguments.dart',
     'lib/src/models/objects/unknown.dart',
+    'lib/src/models/objects/unlinked_call.dart',
     'lib/src/models/objects/vm.dart',
     'lib/src/models/objects/zone.dart',
     'lib/src/models/repositories/allocation_profile.dart',
@@ -208,10 +217,13 @@
     'lib/src/models/repositories/retaining_path.dart',
     'lib/src/models/repositories/sample_profile.dart',
     'lib/src/models/repositories/script.dart',
+    'lib/src/models/repositories/single_target_cache.dart',
     'lib/src/models/repositories/strongly_reachable_instances.dart',
+    'lib/src/models/repositories/subtype_test_cache.dart',
     'lib/src/models/repositories/target.dart',
     'lib/src/models/repositories/top_retaining_instances.dart',
     'lib/src/models/repositories/type_arguments.dart',
+    'lib/src/models/repositories/unlinked_call.dart',
     'lib/src/repositories/allocation_profile.dart',
     'lib/src/repositories/breakpoint.dart',
     'lib/src/repositories/class.dart',
@@ -241,10 +253,13 @@
     'lib/src/repositories/sample_profile.dart',
     'lib/src/repositories/script.dart',
     'lib/src/repositories/settings.dart',
+    'lib/src/repositories/single_target_cache.dart',
     'lib/src/repositories/strongly_reachable_instances.dart',
+    'lib/src/repositories/subtype_test_cache.dart',
     'lib/src/repositories/target.dart',
     'lib/src/repositories/top_retaining_instances.dart',
     'lib/src/repositories/type_arguments.dart',
+    'lib/src/repositories/unlinked_call.dart',
     'lib/src/service/object.dart',
     'lib/tracer.dart',
     'lib/utils.dart',