Pass Device ID in the oauth2/token request. Keep Device ID in local state on Chrome OS.

chrome/browser/chromeos/login/existing_user_controller.cc

Index: chrome/browser/chromeos/login/existing_user_controller.cc
diff --git a/chrome/browser/chromeos/login/existing_user_controller.cc b/chrome/browser/chromeos/login/existing_user_controller.cc
index 54a6820cbac13b39200f5b28d2bd910d0a33ada9..686ea1e0005be38f3defb75e67f63eb279707415 100644
--- a/chrome/browser/chromeos/login/existing_user_controller.cc
+++ b/chrome/browser/chromeos/login/existing_user_controller.cc
@@ -10,6 +10,7 @@
 #include "base/bind_helpers.h"
 #include "base/callback.h"
 #include "base/command_line.h"
+#include "base/guid.h"
 #include "base/logging.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/message_loop/message_loop.h"
@@ -89,6 +90,8 @@ namespace {
 const char kCreateAccountURL[] =
     "https://accounts.google.com/NewAccount?service=mail";
 
+const char kEphemeralUserDeviceIDPrefix[] = "t_";
+
 // Delay for transferring the auth cache to the system profile.
 const long int kAuthCacheTransferDelayMs = 2000;
 
@@ -1119,7 +1122,23 @@ void ExistingUserController::ContinueLoginIfDeviceNotDisabled(
   continuation.Run();
 }
 
-void ExistingUserController::DoCompleteLogin(const UserContext& user_context) {
+void ExistingUserController::DoCompleteLogin(
+    const UserContext& user_context_wo_device_id) {

[achuithb, 2015/05/12 23:25:01]

Maybe call this user_context, and use uc for the stack variable?

we have a few other places where we do something similar to filling in some
state of user_context, and we don't have variable names like this in those
places.

[dzhioev (left Google), 2015/05/13 00:25:17]

'user_context' variable is used 5-6 times in this method. I prefer not to change
its name to keep history clear. I can rename it, if you insist.

+  UserContext user_context = user_context_wo_device_id;
+  std::string known_device_id =

[achuithb, 2015/05/12 23:25:01]

I'd suggest merging the variables known_device_id and new_device_id into
device_id. I think it would simplify the logic below.

[dzhioev (left Google), 2015/05/13 00:25:17]

Done.

+      user_manager::UserManager::Get()->GetKnownUserDeviceId(
+          user_context.GetUserID());
+  if (known_device_id.empty()) {
+    std::string new_device_id = base::GenerateGUID();
+    if (ChromeUserManager::Get()->AreEphemeralUsersEnabled() &&
+        user_context.GetUserID() != ChromeUserManager::Get()->GetOwnerEmail()) {
+      new_device_id = kEphemeralUserDeviceIDPrefix + new_device_id;
+    }
+    user_context.SetDeviceId(new_device_id);
+  } else {
+    user_context.SetDeviceId(known_device_id);
+  }
+
   PerformPreLoginActions(user_context);
 
   if (!time_init_.is_null()) {