Introduce FakeChromeIdentity and FakeChromeIdentityService.

ios/public/provider/chrome/browser/signin/fake_chrome_identity.mm

+// 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.
+
+#import "ios/public/provider/chrome/browser/signin/fake_chrome_identity.h"
+
+#import "base/mac/scoped_nsobject.h"
+
+@implementation FakeChromeIdentity {
+  base::scoped_nsobject<NSString> _userEmail;
+  base::scoped_nsobject<NSString> _gaiaID;
+  base::scoped_nsobject<NSString> _userFullName;
+  base::scoped_nsobject<NSString> _hashedGaiaID;
+}
+
++ (FakeChromeIdentity*)identityWithEmail:(NSString*)email
+                                  gaiaID:(NSString*)gaiaID
+                                    name:(NSString*)name {
+  return
+      [[[FakeChromeIdentity alloc] initWithEmail:email gaiaID:gaiaID name:name]
+          autorelease];
+}
+
+- (instancetype)initWithEmail:(NSString*)email
+                       gaiaID:(NSString*)gaiaID
+                         name:(NSString*)name {
+  self = [super init];
+  if (self) {
+    _userEmail.reset([email copy]);
+    _gaiaID.reset([gaiaID copy]);
+    _userFullName.reset([name copy]);
+    _hashedGaiaID.reset(
+        [[NSString stringWithFormat:@"%@_hashID", name] retain]);
+  }
+  return self;
+}
+
+- (NSString*)userEmail {
+  return _userEmail;
+}
+
+- (NSString*)gaiaID {
+  return _gaiaID;
+}
+
+- (NSString*)userFullName {
+  return _userFullName;
+}
+
+- (NSString*)hashedGaiaID {
+  return _hashedGaiaID;
+}
+
+@end