Consolidate WpHash declaration to a common file

Bug: b/193932763
Test: frameworks/native/test
Change-Id: Ib19f191ed8031b77c059b644fe5df3c8137e6619
diff --git a/services/surfaceflinger/Scheduler/VsyncModulator.h b/services/surfaceflinger/Scheduler/VsyncModulator.h
index b2b0451..2000c54 100644
--- a/services/surfaceflinger/Scheduler/VsyncModulator.h
+++ b/services/surfaceflinger/Scheduler/VsyncModulator.h
@@ -25,6 +25,8 @@
 #include <binder/IBinder.h>
 #include <utils/Timers.h>
 
+#include "../WpHash.h"
+
 namespace android::scheduler {
 
 // State machine controlled by transaction flags. VsyncModulator switches to early phase offsets
@@ -124,12 +126,6 @@
     using Schedule = TransactionSchedule;
     std::atomic<Schedule> mTransactionSchedule = Schedule::Late;
 
-    struct WpHash {
-        size_t operator()(const wp<IBinder>& p) const {
-            return std::hash<IBinder*>()(p.unsafe_get());
-        }
-    };
-
     std::unordered_set<wp<IBinder>, WpHash> mEarlyWakeupRequests GUARDED_BY(mMutex);
     std::atomic<bool> mRefreshRateChangePending = false;