Delete blimp/helium and remove references to it from dependent targets

blimp/helium/BUILD.gn

Index: blimp/helium/BUILD.gn
diff --git a/blimp/helium/BUILD.gn b/blimp/helium/BUILD.gn
deleted file mode 100644
index 4e3fa03b6ed206aa09d4ac33a414a9faf806f989..0000000000000000000000000000000000000000
--- a/blimp/helium/BUILD.gn
+++ /dev/null
@@ -1,84 +0,0 @@
-# Copyright 2016 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.
-
-component("helium") {
-  output_name = "helium"
-  sources = [
-    "compound_syncable.cc",
-    "compound_syncable.h",
-    "errors.h",
-    "lazy_syncable_adapter.h",
-    "lww_register.h",
-    "object_sync_state.cc",
-    "object_sync_state.h",
-    "owned_register.h",
-    "result.cc",
-    "result.h",
-    "revision_generator.cc",
-    "revision_generator.h",
-    "serializable.h",
-    "serializable_struct.cc",
-    "serializable_struct.h",
-    "stream.h",
-    "stream_helpers.cc",
-    "stream_helpers.h",
-    "sync_manager.cc",
-    "sync_manager.h",
-    "syncable.h",
-    "syncable_common.cc",
-    "syncable_common.h",
-    "transport.h",
-    "update_scheduler.cc",
-    "update_scheduler.h",
-    "version_vector.cc",
-    "version_vector.h",
-  ]
-
-  defines = [ "HELIUM_IMPLEMENTATION=1" ]
-
-  deps = [
-    ":helium_export",
-    "//base",
-    "//blimp/common",
-    "//net",
-  ]
-
-  public_deps = [
-    "//blimp/common/proto",
-  ]
-}
-
-source_set("helium_export") {
-  sources = [
-    "blimp_helium_export.h",
-  ]
-}
-
-source_set("unit_tests") {
-  testonly = true
-
-  sources = [
-    "compound_syncable_unittest.cc",
-    "helium_test.h",
-    "lazy_syncable_adapter_unittest.cc",
-    "lww_register_unittest.cc",
-    "mock_objects.cc",
-    "mock_objects.h",
-    "owned_register_unittest.cc",
-    "result_unittest.cc",
-    "revision_generator_unittest.cc",
-    "serializable_struct_unittest.cc",
-    "stream_helpers_unittest.cc",
-    "update_scheduler_unittest.cc",
-    "version_vector_unittest.cc",
-  ]
-
-  deps = [
-    ":helium",
-    "//base",
-    "//blimp/common",
-    "//testing/gmock",
-    "//testing/gtest",
-  ]
-}