Upgrade MTE to SYNC after ASYNC crash.

Bug: 169277947
Test: atest mte_ugprade_test on emulator.
Test: ASSUMPTION_FAILED on non-MTE
Test: ASSUMPTION_FAILED on HWASan
Change-Id: I5328d094ffb106abaa548feb76058c9ebd11d745
diff --git a/init/service.h b/init/service.h
index d233cbf..a82ea77 100644
--- a/init/service.h
+++ b/init/service.h
@@ -168,6 +168,7 @@
     android::base::boot_clock::time_point time_started_;  // time of last start
     android::base::boot_clock::time_point time_crashed_;  // first crash within inspection window
     int crash_count_;                     // number of times crashed within window
+    bool upgraded_mte_ = false;           // whether we upgraded async MTE -> sync MTE before
     std::chrono::minutes fatal_crash_window_ = 4min;  // fatal() when more than 4 crashes in it
     std::optional<std::string> fatal_reboot_target_;  // reboot target of fatal handler
 
@@ -180,6 +181,8 @@
     std::vector<SocketDescriptor> sockets_;
     std::vector<FileDescriptor> files_;
     std::vector<std::pair<std::string, std::string>> environment_vars_;
+    // Environment variables that only get applied to the next run.
+    std::vector<std::pair<std::string, std::string>> once_environment_vars_;
 
     Subcontext* subcontext_;
     Action onrestart_;  // Commands to execute on restart.