Add a mojo interface for AccountId

components/signin/public/interfaces/account_id_traits.h

Index: components/signin/public/interfaces/account_id_traits.h
diff --git a/components/signin/public/interfaces/account_id_traits.h b/components/signin/public/interfaces/account_id_traits.h
new file mode 100644
index 0000000000000000000000000000000000000000..33a900a006e1a616a95cceeefcb470e5249bc031
--- /dev/null
+++ b/components/signin/public/interfaces/account_id_traits.h
@@ -0,0 +1,97 @@
+// Copyright 2017 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 COMPONENTS_SIGNIN_PUBLIC_INTERFACES_ACCOUNT_ID_TRAITS_H_
+#define COMPONENTS_SIGNIN_PUBLIC_INTERFACES_ACCOUNT_ID_TRAITS_H_
+
+#include <string>
+
+#include "components/signin/core/account_id/account_id.h"
+#include "components/signin/public/interfaces/account_id.mojom.h"
+
+namespace mojo {
+
+template <>
+struct EnumTraits<signin::mojom::AccountType, AccountType> {
+  static signin::mojom::AccountType ToMojom(AccountType input) {
+    switch (input) {
+      case AccountType::UNKNOWN:
+        return signin::mojom::AccountType::UNKNOWN;
+      case AccountType::GOOGLE:
+        return signin::mojom::AccountType::GOOGLE;
+      case AccountType::ACTIVE_DIRECTORY:
+        return signin::mojom::AccountType::ACTIVE_DIRECTORY;
+    }
+    NOTREACHED();
+    return signin::mojom::AccountType::UNKNOWN;
+  }
+
+  static bool FromMojom(signin::mojom::AccountType input,
+                        AccountType* out) {
+    switch (input) {
+      case signin::mojom::AccountType::UNKNOWN:
+        *out = AccountType::UNKNOWN;
+        return true;
+      case signin::mojom::AccountType::GOOGLE:
+        *out = AccountType::GOOGLE;
+        return true;
+      case signin::mojom::AccountType::ACTIVE_DIRECTORY:
+        *out = AccountType::ACTIVE_DIRECTORY;
+        return true;
+    }
+    NOTREACHED();
+    return false;
+  }
+};
+
+
+template <>
+struct StructTraits<signin::mojom::AccountIdDataView, AccountId> {
+  static AccountType account_type(const AccountId& r) {
+    return r.GetAccountType();
+  }
+  static std::string id(const AccountId& r) {
+    switch (r.GetAccountType()) {
+      case AccountType::GOOGLE:
+        return r.GetGaiaId();
+      case AccountType::ACTIVE_DIRECTORY:
+        return r.GetObjGuid();
+      case AccountType::UNKNOWN:
+        break;

[James Cook, 2017/01/06 20:54:32]

Question: So trying to get an id() of an unknown account type is an error (hence
NOTREACHED below)?

[xiyuan, 2017/01/06 21:49:35]

Good question. And we actually have use of such AccountIds (contrary to my
believing). The failed tests hit that. Those are users with only emails that we
use in tests. And we probably also use them for legacy users that has not
migrated to new code (that populate them with their gaia ids).

Changed this to return empty string for such users. And updated Read function
below to allow UNKNOWN type AccountId to be constructed with only user_email or
gaia id. Also added a comment to doc it.

+    }
+    NOTREACHED();
+    return "";
+  }
+  static std::string user_email(const AccountId& r) {
+    return r.GetUserEmail();
+  }
+
+  static bool Read(signin::mojom::AccountIdDataView data, AccountId* out) {
+    AccountType account_type;
+    std::string id;
+    std::string user_email;
+    if (!data.ReadAccountType(&account_type) ||
+        !data.ReadId(&id) ||
+        !data.ReadUserEmail(&user_email)) {
+      return false;
+    }
+
+    switch (account_type) {
+      case AccountType::GOOGLE:
+        *out = AccountId::FromUserEmailGaiaId(user_email, id);
+        break;
+      case AccountType::ACTIVE_DIRECTORY:
+        *out = AccountId::AdFromUserEmailObjGuid(user_email, id);
+        break;
+      case AccountType::UNKNOWN:
+        return false;
+    }
+
+    return out->is_valid();
+  }
+};
+
+}  // namespace mojo
+
+#endif  // COMPONENTS_SIGNIN_PUBLIC_INTERFACES_ACCOUNT_ID_TRAITS_H_