[Magnifier-26] Wire up frame callback for realsies

Test: none yet
Bug: 73810478
Bug: 72041926
Change-Id: I7154ed4b3d2cd820dc8c8ff55eed130be87d1606
diff --git a/libs/hwui/renderthread/DrawFrameTask.h b/libs/hwui/renderthread/DrawFrameTask.h
index ea51ae4..d8c43e0 100644
--- a/libs/hwui/renderthread/DrawFrameTask.h
+++ b/libs/hwui/renderthread/DrawFrameTask.h
@@ -74,6 +74,10 @@
 
     void run();
 
+    void setFrameCallback(std::function<void(int64_t)>&& callback) {
+        mFrameCallback = std::move(callback);
+    }
+
 private:
     void postAndWait();
     bool syncFrameState(TreeInfo& info);
@@ -96,6 +100,8 @@
     int64_t mSyncQueued;
 
     int64_t mFrameInfo[UI_THREAD_FRAME_INFO_SIZE];
+
+    std::function<void(int64_t)> mFrameCallback;
 };
 
 } /* namespace renderthread */