Firestore project: Import of API interfaces.

Import of firebase-ios-sdk from Github.

  - 07f4695 Updates Changelog for 4.5.0 release (firebase#908) by Zsika Phillip <protocol86@users.noreply.github.com>
  - 2b82a2e Allow serializing arbitrary length FieldValues (firebase#889) by rsgowman <rgowman>
  - 3e41f25 Fix test failures that occur during prod build (firebase#910) by rsgowman <rgowman>
  - f122cf7 Fix MutationQueue issue resulting in re-sending acknowled... by Michael Lehenbauer <mikelehen@gmail.com>
  - 7522314 Partial wrapping of pb_ostream_t (pt2) (firebase#903) by rsgowman <rgowman>
  - 0d3adb1 Partial wrapping of pb_ostream_t (pt1) (firebase#899) by rsgowman <rgowman>
  - e41f4b1 Merge Release 4.10.1 into Master (firebase#896) by zxu <zxu>
  - 2ae36f1 [De]Serialize FieldValue map_values ("Objects") (firebase#878) by rsgowman <rgowman>
  - 5930ad2 Factor out a universal build script (firebase#884) by Gil <mcg>
  - 8ef0f14 Adds Email link sign-in (firebase#882) by Paul Beusterien <paulbeusterien>
  - 0b8f216 Merge pull request firebase#880 from firebase/release-4.10.0 by Paul Beusterien <paulbeusterien>
  - 8311c64 port paths to FSTDocumentKey (firebase#877) by zxu <zxu>
  - 34ebf10 Add 10 second timeout waiting for connection before clien... by Michael Lehenbauer <mikelehen@gmail.com>
  - 1c40e7a add converters and port paths to FSTQuery (firebase#869) by zxu <zxu>
  - 9b5b4d8 Serialize (and deserialize) string values (firebase#864) by rsgowman <rgowman>
  - c6f73f7 Fix the issue completion handler is not triggered in subs... by Chen Liang <chliang>
  - 1ecf690 Add FieldValue.boolean_value() (firebase#862) by rsgowman <rgowman>
  - 3e7c062 replacing Auth by C++ auth implementation (firebase#802) by zxu <zxu>
  - 13aeb61 Eliminate TypedValue and serialize direct from FieldValue... by rsgowman <rgowman>

ORIGINAL_AUTHOR=Gil <wilhuff@github.com>
PiperOrigin-RevId: 188809445

Firestore/core/include/firebase/firestore/firestore_errors.h

@@ -0,0 +1,115 @@
+/*
+ * Copyright 2018 Google
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef FIRESTORE_CORE_INCLUDE_FIREBASE_FIRESTORE_FIRESTORE_ERRORS_H_
+#define FIRESTORE_CORE_INCLUDE_FIREBASE_FIRESTORE_FIRESTORE_ERRORS_H_
+
+namespace firebase {
+namespace firestore {
+
+/**
+ * Error codes used by Cloud Firestore.
+ *
+ * The codes are in sync with the Firestore iOS client SDK header file
+ * FIRFirestoreErrors.h.
+ */
+enum FirestoreErrorCode {
+  /**
+   * The operation completed successfully. NSError objects will never have a
+   * code with this value.
+   */
+  Ok = 0,
+
+  /** The operation was cancelled (typically by the caller). */
+  Cancelled = 1,
+
+  /** Unknown error or an error from a different error domain. */
+  Unknown = 2,
+
+  /**
+   * Client specified an invalid argument. Note that this differs from
+   * FailedPrecondition. InvalidArgument indicates arguments that are
+   * problematic regardless of the state of the system (e.g., an invalid field
+   * name).
+   */
+  InvalidArgument = 3,
+
+  /**
+   * Deadline expired before operation could complete. For operations that
+   * change the state of the system, this error may be returned even if the
+   * operation has completed successfully. For example, a successful response
+   * from a server could have been delayed long enough for the deadline to
+   * expire.
+   */
+  DeadlineExceeded = 4,
+
+  /** Some requested document was not found. */
+  NotFound = 5,
+
+  /** Some document that we attempted to create already exists. */
+  AlreadyExists = 6,
+
+  /** The caller does not have permission to execute the specified operation. */
+  PermissionDenied = 7,
+
+  /**
+   * Some resource has been exhausted, perhaps a per-user quota, or perhaps the
+   * entire file system is out of space.
+   */
+  ResourceExhausted = 8,
+
+  /**
+   * Operation was rejected because the system is not in a state required for
+   * the operation's execution.
+   */
+  FailedPrecondition = 9,
+
+  /**
+   * The operation was aborted, typically due to a concurrency issue like
+   * transaction aborts, etc.
+   */
+  Aborted = 10,
+
+  /** Operation was attempted past the valid range. */
+  OutOfRange = 11,
+
+  /** Operation is not implemented or not supported/enabled. */
+  Unimplemented = 12,
+
+  /**
+   * Internal errors. Means some invariants expected by underlying system has
+   * been broken. If you see one of these errors, something is very broken.
+   */
+  Internal = 13,
+
+  /**
+   * The service is currently unavailable. This is a most likely a transient
+   * condition and may be corrected by retrying with a backoff.
+   */
+  Unavailable = 14,
+
+  /** Unrecoverable data loss or corruption. */
+  DataLoss = 15,
+
+  /** The request does not have valid authentication credentials for the
+     operation. */
+  Unauthenticated = 16
+};
+
+}  // namespace firestore
+}  // namespace firebase
+
+#endif  // FIRESTORE_CORE_INCLUDE_FIREBASE_FIRESTORE_FIRESTORE_ERRORS_H_