Introduce FakeChromeIdentity and FakeChromeIdentityService.

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

Index: ios/public/provider/chrome/browser/signin/fake_chrome_identity.h
diff --git a/ios/public/provider/chrome/browser/signin/fake_chrome_identity.h b/ios/public/provider/chrome/browser/signin/fake_chrome_identity.h
new file mode 100644
index 0000000000000000000000000000000000000000..cc7656a6f1e126af701772e13418bff9aaa9bff5
--- /dev/null
+++ b/ios/public/provider/chrome/browser/signin/fake_chrome_identity.h
@@ -0,0 +1,21 @@
+// 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.
+
+#ifndef IOS_PUBLIC_PROVIDER_CHROME_BROWSER_SIGNIN_FAKE_CHROME_IDENTITY_H_
+#define IOS_PUBLIC_PROVIDER_CHROME_BROWSER_SIGNIN_FAKE_CHROME_IDENTITY_H_
+
+#import "ios/public/provider/chrome/browser/signin/chrome_identity.h"
+
+// A fake ChromeIdentity used for testing.
+@interface FakeChromeIdentity : ChromeIdentity
+
+// Returns a new fake ChromeIdentity based on |email|, |gaiaID| and |name|.

[msarda, 2016/07/07 11:58:06]

s/a new/an autoreleased

[bzanotti, 2016/07/07 12:48:11]

Done.

+// The hashedGaiaID will be derived from |name|.

[sdefresne, 2016/07/07 12:12:40]

nit: The hashed GaiaID

[bzanotti, 2016/07/07 12:48:11]

I was referring to the property |hashedGaiaID|. Updated to make this more clear.

++ (FakeChromeIdentity*)identityWithEmail:(NSString*)email
+                                  gaiaID:(NSString*)gaiaID
+                                    name:(NSString*)name;
+
+@end
+
+#endif  // IOS_PUBLIC_PROVIDER_CHROME_BROWSER_SIGNIN_FAKE_CHROME_IDENTITY_H_