Introduce new chrome.easyUnlock APIs for getting the sign-in challenge and using it to sign-in the …

chrome/common/extensions/api/easy_unlock_private.idl

Index: chrome/common/extensions/api/easy_unlock_private.idl
diff --git a/chrome/common/extensions/api/easy_unlock_private.idl b/chrome/common/extensions/api/easy_unlock_private.idl
index 6766a00d61d852264fae622f1f2391fee133181c..1e62e0eeb4ae9efe102d2799aef6c7c93a03ee2f 100644
--- a/chrome/common/extensions/api/easy_unlock_private.idl
+++ b/chrome/common/extensions/api/easy_unlock_private.idl
@@ -259,5 +259,14 @@
 
     // Gets the remote device list.
     static void getRemoteDevices(GetRemoteDevicesCallback callback);
+
+    // Gets the sign-in challenge for the current user.
+    static void getSignInChallenge(DataCallback callback);
+
+    // Tries to sign-in the current user with a secret obtained by decrypting
+    // the sign-in challenge. Check chrome.runtime.lastError for failures. Upon
+    // success, the user session will be started.
+    static void trySignInSecret(ArrayBuffer signInSecret,
+                                EmptyCallback callback);
   };
 };