Notify the framework when an adb key is authorized

Bug: 124076524
Test: atest AdbDebuggingManagerTest
Change-Id: If73b81ca73ba4d64763cf49c1bbe42de81fa1cb6
diff --git a/adb/transport.h b/adb/transport.h
index f4490ed..3473ca2 100644
--- a/adb/transport.h
+++ b/adb/transport.h
@@ -274,6 +274,9 @@
     std::string device;
     std::string devpath;
 
+    // Used to provide the key to the framework.
+    std::string auth_key;
+
     bool IsTcpDevice() const { return type == kTransportLocal; }
 
 #if ADB_HOST