SF: Deduplicate ID concat of DisplayDevice traces

Bug: 241285876
Test: Perfetto
Change-Id: Ibe39de0f144066be8c6111915d9c1394565ec541
diff --git a/services/surfaceflinger/DisplayDevice.cpp b/services/surfaceflinger/DisplayDevice.cpp
index 5b6591a..2ffe92b 100644
--- a/services/surfaceflinger/DisplayDevice.cpp
+++ b/services/surfaceflinger/DisplayDevice.cpp
@@ -63,13 +63,14 @@
         mDisplayToken(args.displayToken),
         mSequenceId(args.sequenceId),
         mCompositionDisplay{args.compositionDisplay},
-        mActiveModeFPSTrace("ActiveModeFPS -" + to_string(getId())),
-        mActiveModeFPSHwcTrace("ActiveModeFPS_HWC -" + to_string(getId())),
-        mRenderFrameRateFPSTrace("RenderRateFPS -" + to_string(getId())),
+        mActiveModeFPSTrace(concatId("ActiveModeFPS")),
+        mActiveModeFPSHwcTrace(concatId("ActiveModeFPS_HWC")),
+        mRenderFrameRateFPSTrace(concatId("RenderRateFPS")),
         mPhysicalOrientation(args.physicalOrientation),
         mIsPrimary(args.isPrimary),
         mRequestedRefreshRate(args.requestedRefreshRate),
-        mRefreshRateSelector(std::move(args.refreshRateSelector)) {
+        mRefreshRateSelector(std::move(args.refreshRateSelector)),
+        mDesiredActiveModeChanged(concatId("DesiredActiveModeChanged"), false) {
     mCompositionDisplay->editState().isSecure = args.isSecure;
     mCompositionDisplay->createRenderSurface(
             compositionengine::RenderSurfaceCreationArgsBuilder()
diff --git a/services/surfaceflinger/DisplayDevice.h b/services/surfaceflinger/DisplayDevice.h
index a044534..a40f310 100644
--- a/services/surfaceflinger/DisplayDevice.h
+++ b/services/surfaceflinger/DisplayDevice.h
@@ -269,6 +269,11 @@
     void dump(utils::Dumper&) const;
 
 private:
+    template <size_t N>
+    inline std::string concatId(const char (&str)[N]) const {
+        return std::string(ftl::Concat(str, ' ', getId().value).str());
+    }
+
     const sp<SurfaceFlinger> mFlinger;
     HWComposer& mHwComposer;
     const wp<IBinder> mDisplayToken;
@@ -316,8 +321,7 @@
 
     mutable std::mutex mActiveModeLock;
     ActiveModeInfo mDesiredActiveMode GUARDED_BY(mActiveModeLock);
-    TracedOrdinal<bool> mDesiredActiveModeChanged GUARDED_BY(mActiveModeLock) =
-            {ftl::Concat("DesiredActiveModeChanged-", getId().value).c_str(), false};
+    TracedOrdinal<bool> mDesiredActiveModeChanged GUARDED_BY(mActiveModeLock);
 
     ActiveModeInfo mUpcomingActiveMode GUARDED_BY(kMainThreadContext);
     bool mIsModeSetPending GUARDED_BY(kMainThreadContext) = false;