Fix media_cas_proxy_sdk build issue.

Add example binary for testing building the SDK after 'git clone' from our repo.

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Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=227583629

common/status.cc

@@ -0,0 +1,74 @@
+////////////////////////////////////////////////////////////////////////////////
+// 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.
+////////////////////////////////////////////////////////////////////////////////
+
+#include "common/status.h"
+
+#include <string>
+
+#include "absl/base/macros.h"
+#include "absl/strings/str_cat.h"
+#include "util/error_space.h"
+
+namespace widevine {
+
+namespace {
+
+const char* kGenericErrorStatusMessage[] = {"OK",
+                                            "unknown_error",
+                                            "unknown_error",
+                                            "invalid_argument",
+                                            "unknown_error",
+                                            "not_found",
+                                            "already_exists",
+                                            "permission_denied",
+                                            "unknown_error",
+                                            "unknown_error",
+                                            "unknown_error",
+                                            "unknown_error",
+                                            "unimplemented",
+                                            "internal",
+                                            "unavailable"};
+
+}  // namespace
+
+class GenericErrorSpace : public util::ErrorSpaceImpl<GenericErrorSpace> {
+ public:
+  static std::string space_name();
+  static std::string code_to_string(int code);
+};
+
+std::string GenericErrorSpace::space_name() { return "generic"; }
+
+std::string GenericErrorSpace::code_to_string(int code) {
+  static_assert(
+      ABSL_ARRAYSIZE(kGenericErrorStatusMessage) == error::NUM_ERRORS,
+      "mismatching generic error status message and generic error status.");
+
+  if (code >= 0 && code < error::NUM_ERRORS)
+    return kGenericErrorStatusMessage[code];
+  return std::to_string(code);
+}
+
+
+
+const util::ErrorSpace* Status::canonical_space() {
+  return GenericErrorSpace::Get();
+}
+
+std::string Status::ToString() const {
+  if (status_code_ == error::OK) return "OK";
+  return absl::StrCat("Errors::", error_space_->String(status_code_), ": ",
+                      error_message_);
+}
+
+std::ostream& operator<<(std::ostream& os, const Status& x) {
+  os << x.ToString();
+  return os;
+}
+
+}  // namespace widevine