Use HTML messages to inform GAIA about deviceId.

chrome/browser/ui/webui/chromeos/login/gaia_screen_handler.h

Index: chrome/browser/ui/webui/chromeos/login/gaia_screen_handler.h
diff --git a/chrome/browser/ui/webui/chromeos/login/gaia_screen_handler.h b/chrome/browser/ui/webui/chromeos/login/gaia_screen_handler.h
index 463442826943bf9feab2710c052553109a928ce3..8d1d639a4682014529220d716a58bb445b2b332c 100644
--- a/chrome/browser/ui/webui/chromeos/login/gaia_screen_handler.h
+++ b/chrome/browser/ui/webui/chromeos/login/gaia_screen_handler.h
@@ -133,6 +133,8 @@ class GaiaScreenHandler : public BaseScreenHandler {
 
   void HandleToggleEasyBootstrap();
 
+  void HandleAttemptLogin(const std::string& email);
+
   void HandleToggleWebviewSignin();
 
   // This is called when ConsumerManagementService::SetOwner() returns.
@@ -202,6 +204,9 @@ class GaiaScreenHandler : public BaseScreenHandler {
 
   SigninScreenHandlerDelegate* Delegate();
 
+  // Returns temporary unused device Id.
+  std::string GetTemporaryDeviceId();
+
   // Current state of Gaia frame.
   FrameState frame_state_;
 
@@ -268,6 +273,10 @@ class GaiaScreenHandler : public BaseScreenHandler {
   // GAIA extension loader.
   scoped_ptr<ScopedGaiaAuthExtension> auth_extension_;
 
+  // Temporary DeviceId to be used for new users.
+  // If it's empty, new deviceId should be generated.
+  std::string temporary_device_id_;
+
   base::WeakPtrFactory<GaiaScreenHandler> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(GaiaScreenHandler);