[TimeStats] Track RenderEngine time per frame.

Bug: 144037240
Test: dumpsys SurfaceFlinger --timestats -dump
Change-Id: I7a4dd680ed08e3a7a05e3fd08d5e133e9d394193
diff --git a/services/surfaceflinger/CompositionEngine/src/CompositionEngine.cpp b/services/surfaceflinger/CompositionEngine/src/CompositionEngine.cpp
index be8646c..5eabecd 100644
--- a/services/surfaceflinger/CompositionEngine/src/CompositionEngine.cpp
+++ b/services/surfaceflinger/CompositionEngine/src/CompositionEngine.cpp
@@ -64,6 +64,14 @@
     mRenderEngine = std::move(renderEngine);
 }
 
+TimeStats& CompositionEngine::getTimeStats() const {
+    return *mTimeStats.get();
+}
+
+void CompositionEngine::setTimeStats(const std::shared_ptr<TimeStats>& timeStats) {
+    mTimeStats = timeStats;
+}
+
 bool CompositionEngine::needsAnotherUpdate() const {
     return mNeedsAnotherUpdate;
 }