Fix leak/crash in exit

Bug: 120440607
Test: hwuimacro32 doesn't crash
Change-Id: I35b7a924e338efb314f07b923ba22ffcf98f75ee
diff --git a/libs/hwui/thread/ThreadBase.h b/libs/hwui/thread/ThreadBase.h
index f9de8a5..8cdcc46 100644
--- a/libs/hwui/thread/ThreadBase.h
+++ b/libs/hwui/thread/ThreadBase.h
@@ -27,7 +27,7 @@
 
 namespace android::uirenderer {
 
-class ThreadBase : protected Thread {
+class ThreadBase : public Thread {
     PREVENT_COPY_AND_ASSIGN(ThreadBase);
 
 public: