Framework code for Attached Choreographer.

Allows a direct association of a Layer (via LayerHistory) to attached
choreographer.
The EventThread checks whether the vsync is in phase for a
choreographer.

Bug: 255838011
Test: atest AttachedChoreographerNativeTest
Change-Id: I9cb35bced5e6d4509609ad7698ab2902a31d5b98
diff --git a/services/surfaceflinger/Scheduler/EventThread.h b/services/surfaceflinger/Scheduler/EventThread.h
index b86553b..aa27091 100644
--- a/services/surfaceflinger/Scheduler/EventThread.h
+++ b/services/surfaceflinger/Scheduler/EventThread.h
@@ -97,6 +97,9 @@
     const uid_t mOwnerUid;
     const EventRegistrationFlags mEventRegistration;
 
+    /** The frame rate set to the attached choreographer. */
+    Fps frameRate;
+
 private:
     virtual void onFirstRef();
     EventThread* const mEventThread;