Take 'sources' argument by const reference

Bug: b/270049345
Test: atest inputflinger_tests:LatencyTrackerTest
Flag: NONE adding a reference

Change-Id: I0568ea90da984ae6f906d8bf018de9a423834858
diff --git a/services/inputflinger/dispatcher/InputEventTimeline.h b/services/inputflinger/dispatcher/InputEventTimeline.h
index e9deb2d..1756944 100644
--- a/services/inputflinger/dispatcher/InputEventTimeline.h
+++ b/services/inputflinger/dispatcher/InputEventTimeline.h
@@ -76,7 +76,7 @@
 
 struct InputEventTimeline {
     InputEventTimeline(bool isDown, nsecs_t eventTime, nsecs_t readTime, uint16_t vendorId,
-                       uint16_t productId, std::set<InputDeviceUsageSource> sources);
+                       uint16_t productId, const std::set<InputDeviceUsageSource>& sources);
     const bool isDown; // True if this is an ACTION_DOWN event
     const nsecs_t eventTime;
     const nsecs_t readTime;