Introduce Identity Service and its initial usage

chrome/browser/extensions/api/identity/identity_get_profile_user_info_function.cc

Index: chrome/browser/extensions/api/identity/identity_get_profile_user_info_function.cc
diff --git a/chrome/browser/extensions/api/identity/identity_get_profile_user_info_function.cc b/chrome/browser/extensions/api/identity/identity_get_profile_user_info_function.cc
index 0940586623b4d09a5a3d803c6aa7f49d128616ac..2a7c6cd9db0b6b8050a7304df66289a4f72d580d 100644
--- a/chrome/browser/extensions/api/identity/identity_get_profile_user_info_function.cc
+++ b/chrome/browser/extensions/api/identity/identity_get_profile_user_info_function.cc
@@ -6,11 +6,12 @@
 
 #include "chrome/browser/extensions/api/identity/identity_constants.h"
 #include "chrome/browser/profiles/profile.h"
-#include "chrome/browser/signin/signin_manager_factory.h"
 #include "chrome/common/extensions/api/identity.h"
-#include "components/signin/core/browser/signin_manager.h"
+#include "content/public/common/service_manager_connection.h"
 #include "extensions/common/extension.h"
 #include "extensions/common/permissions/permissions_data.h"
+#include "services/identity/public/interfaces/constants.mojom.h"
+#include "services/service_manager/public/cpp/connector.h"
 
 namespace extensions {
 
@@ -25,16 +26,28 @@ ExtensionFunction::ResponseAction IdentityGetProfileUserInfoFunction::Run() {
     return RespondNow(Error(identity_constants::kOffTheRecord));
   }
 
-  AccountInfo account = SigninManagerFactory::GetForProfile(
-      GetProfile())->GetAuthenticatedAccountInfo();
+  if (!identity_manager_.is_bound()) {

[Ken Rockot(use gerrit already), 2017/03/21 14:53:09]

It's been a while, but IIRC this test is redundant because we never Run() a
function instance more than once, i.e. an instance is created for every API
call. Could omit this or at worst make it a DCHECK

Ideally we would just have the renderer maintain an IdentityManagerPtr, and the
native bindings for this API use that Ptr directly. I wonder if we could do this
relatively painlessly in a follow-up CL. It would be a nice end-to-end
demonstration of the "correct" way to convert an extension API to use services.

[blundell, 2017/03/21 16:08:47]

+1000, I'd love to use this effort as a demonstration of the potential win wrt
extensions here. I'm totally willing to add some extra eng investment if that's
a possibility.

[blundell, 2017/03/24 09:37:59]

Done.

+    content::BrowserContext::GetConnectorFor(GetProfile())
+        ->BindInterface(identity::mojom::kServiceName,
+                        mojo::MakeRequest(&identity_manager_));
+  }
+
+  identity_manager_->GetPrimaryAccountId(base::Bind(
+      &IdentityGetProfileUserInfoFunction::OnReceivedPrimaryAccountId, this));
+
+  return RespondLater();
+}
+
+void IdentityGetProfileUserInfoFunction::OnReceivedPrimaryAccountId(
+    const base::Optional<AccountId>& account_id) {
   api::identity::ProfileUserInfo profile_user_info;
-  if (extension()->permissions_data()->HasAPIPermission(
-          APIPermission::kIdentityEmail)) {
-    profile_user_info.email = account.email;
-    profile_user_info.id = account.gaia;
+  if (account_id && extension()->permissions_data()->HasAPIPermission(

[msarda, 2017/03/23 10:48:57]

I think there is no point in making a call to get the primary account info if
the extension does not have the API identity.email permissions. Consider moving
this check before calling the service.

[blundell, 2017/03/24 09:37:59]

Done.

+                        APIPermission::kIdentityEmail)) {
+    profile_user_info.email = account_id->GetUserEmail();
+    profile_user_info.id = account_id->GetGaiaId();
   }
 
-  return RespondNow(OneArgument(profile_user_info.ToValue()));
+  Respond(OneArgument(profile_user_info.ToValue()));
 }
 
 }  // namespace extensions