SF: Cleanup EventThread Part 2

De-refbase EventThread and a bunch of related classes. Convert from
usign StrongPointer to std::unique_ptr to hold owned references, or bare
pointers for unowned references.

I did not see any need for using std::shared_ptr, or anything else, as
SurfaceFlinger appeared to own all the objects, and they were created
once and not really destroyed afterwards.

Test: Things seem to still work on a Pixel XL
Bug: None

Change-Id: Ifff32118d31bc1bb51e38df695ebe5cf86d2bb6d
diff --git a/services/surfaceflinger/MessageQueue.cpp b/services/surfaceflinger/MessageQueue.cpp
index c9c3989..5a6ff4d 100644
--- a/services/surfaceflinger/MessageQueue.cpp
+++ b/services/surfaceflinger/MessageQueue.cpp
@@ -82,7 +82,7 @@
     mHandler = new Handler(*this);
 }
 
-void MessageQueue::setEventThread(const sp<EventThread>& eventThread) {
+void MessageQueue::setEventThread(EventThread* eventThread) {
     if (mEventThread == eventThread) {
         return;
     }