[v8] Remove dependency on the Promises SDK (#187)

* [v8] Replace read keychain API with completion handler based API (#182)

* [v8] Replace write keychain API with completion handler based API (#183)

* [v8] Replace remove keychain API with completion handler based API (#184)

* [v8] Replace remove keychain API with completion handler based API

* Update GoogleUtilities/Environment/SecureStorage/GULKeychainStorage.m

* [v8] Fix tests, docs, and imports following `GULKeychainStorage` API changes (#185)

* [v8] Remove Promises API and dependency specifications (#186)

* [v8] Remove Promises API and dependency specifications

* Remove other header

* [v8] Add changelog for removal of Promises dependency

* [v8] Remove extraneous parameter from removeObject API (#188)

CHANGELOG.md

@@ -17,6 +17,15 @@
       | tvOS  | **13.0**  |
       | macOS  | **10.15**  |
       | watchOS  | 7.0  |
+- Remove dependency on `FBLPromises`. The following public API have
+  been removed:
+  - `- [NSURLSession gul_dataTaskPromiseWithRequest:]`
+  - `GULURLSessionDataResponse`
+  The following promise-based public API have been replaced with
+  completion handler-based alternatives.
+  - `- [GULKeychainStorage getObjectForKey:objectClass:accessGroup:]`
+  - `- [GULKeychainStorage setObject:forKey:accessGroup:]`
+  - `- [GULKeychainStorage removeObjectForKey:accessGroup:]`
 
 # 7.13.3
 - Rename parameter placeholder in `GULSecureCoding` unarchiving API to avoid

GoogleUtilities.podspec

@@ -47,7 +47,6 @@ other Google CocoaPods. They're not intended for direct public usage.
       'third_party/IsAppEncrypted/**/*.[mh]'
     ]
     es.public_header_files = 'GoogleUtilities/Environment/Public/GoogleUtilities/*.h'
-    es.dependency 'PromisesObjC', '>= 1.2', '< 3.0'
     es.dependency 'GoogleUtilities/Privacy'
     es.frameworks = [
       'Security'

GoogleUtilities/Environment/Public/GoogleUtilities/GULKeychainStorage.h

@@ -16,8 +16,6 @@
 
 #import <Foundation/Foundation.h>
 
-@class FBLPromise<ValueType>;
-
 NS_ASSUME_NONNULL_BEGIN
 
 /// The class provides a convenient, multiplatform abstraction of the Keychain.
@@ -34,42 +32,46 @@ NS_ASSUME_NONNULL_BEGIN
  */
 - (instancetype)initWithService:(NSString *)service;
 
-/**
- * Get an object by key.
- * @param key The key.
- * @param objectClass The expected object class required by `NSSecureCoding`.
- * @param accessGroup The Keychain Access Group.
- *
- * @return Returns a promise. It is resolved with an object stored by key if exists. It is resolved
- * with `nil` when the object not found. It fails on a Keychain error.
- */
-- (FBLPromise<id<NSSecureCoding>> *)getObjectForKey:(NSString *)key
-                                        objectClass:(Class)objectClass
-                                        accessGroup:(nullable NSString *)accessGroup;
+/// Get an object by key.
+/// @param key The key.
+/// @param objectClass The expected object class required by `NSSecureCoding`.
+/// @param accessGroup The Keychain Access Group.
+/// @param completionHandler The completion handler to call when the
+/// synchronized keychain read is complete. An error is passed to the
+/// completion handler if the keychain read fails. Else, the object stored in
+/// the keychain, or `nil` if it does not exist, is passed to the completion
+/// handler.
+- (void)getObjectForKey:(NSString *)key
+            objectClass:(Class)objectClass
+            accessGroup:(nullable NSString *)accessGroup
+      completionHandler:
+          (void (^)(id<NSSecureCoding> _Nullable obj, NSError *_Nullable error))completionHandler;
 
-/**
- * Saves the given object by the given key.
- * @param object The object to store.
- * @param key The key to store the object. If there is an existing object by the key, it will be
- * overridden.
- * @param accessGroup The Keychain Access Group.
- *
- * @return Returns which is resolved with `[NSNull null]` on success.
- */
-- (FBLPromise<NSNull *> *)setObject:(id<NSSecureCoding>)object
-                             forKey:(NSString *)key
-                        accessGroup:(nullable NSString *)accessGroup;
+/// Saves the given object by the given key.
+/// @param object The object to store.
+/// @param key The key to store the object. If there is an existing object by the key, it will be
+/// overridden.
+/// @param accessGroup The Keychain Access Group.
+/// @param completionHandler  The completion handler to call when the
+/// synchronized keychain write is complete. An error is passed to the
+/// completion handler if the keychain read fails. Else, the object written to
+/// the keychain is passed to the completion handler.
+- (void)setObject:(id<NSSecureCoding>)object
+               forKey:(NSString *)key
+          accessGroup:(nullable NSString *)accessGroup
+    completionHandler:
+        (void (^)(id<NSSecureCoding> _Nullable obj, NSError *_Nullable error))completionHandler;
 
-/**
- * Removes the object by the given key.
- * @param key The key to store the object. If there is an existing object by the key, it will be
- * overridden.
- * @param accessGroup The Keychain Access Group.
- *
- * @return Returns which is resolved with `[NSNull null]` on success.
- */
-- (FBLPromise<NSNull *> *)removeObjectForKey:(NSString *)key
-                                 accessGroup:(nullable NSString *)accessGroup;
+/// Removes the object by the given key.
+/// @param key The key to store the object. If there is an existing object by
+/// the key, it will be overridden.
+/// @param accessGroup The Keychain Access Group.
+/// @param completionHandler The completion handler to call when the
+/// synchronized keychain removal is complete. An error is passed to the
+/// completion handler if the keychain removal fails.
+- (void)removeObjectForKey:(NSString *)key
+               accessGroup:(nullable NSString *)accessGroup
+         completionHandler:(void (^)(NSError *_Nullable error))completionHandler;
 
 #if TARGET_OS_OSX
 /// If not `nil`, then only this keychain will be used to save and read data (see