Refactor and cleanup codes. No functional changes.

util/BUILD

@@ -0,0 +1,43 @@
+################################################################################
+# Copyright 2017 Google LLC.
+#
+# This software is licensed under the terms defined in the Widevine Master
+# License Agreement. For a copy of this agreement, please contact
+# widevine-licensing@google.com.
+################################################################################
+
+package(
+    default_visibility = ["//visibility:public"],
+)
+
+
+filegroup(
+    name = "binary_release_files",
+    srcs = [
+        "error_space.h",
+    ],
+)
+
+cc_library(
+    name = "error_space",
+    hdrs = ["error_space.h"],
+)
+
+cc_library(
+    name = "proto_status",
+    hdrs = ["proto_status.h"],
+    deps = [
+        "@protobuf_repo//:protobuf",
+        "//util:error_space",
+    ],
+)
+
+cc_test(
+    name = "error_space_test",
+    srcs = ["error_space_test.cc"],
+    deps = [
+        ":error_space",
+        "//testing:gunit_main",
+    ],
+)
+