Add unit test for AidlPowerHalWrapper

Bug: b/195990840
Test: atest libsurfaceflinger_unittest:libsurfaceflinger_unittest.AidlPowerHalWrapperTest
Change-Id: I5b2197904445a83e5d586aa6331ccc3d46db22a3
diff --git a/services/surfaceflinger/SurfaceFlinger.cpp b/services/surfaceflinger/SurfaceFlinger.cpp
index 9f5a7df..5f2b5eb 100644
--- a/services/surfaceflinger/SurfaceFlinger.cpp
+++ b/services/surfaceflinger/SurfaceFlinger.cpp
@@ -729,7 +729,9 @@
             if (renderEngineTid.has_value()) {
                 tidList.emplace_back(*renderEngineTid);
             }
-            mPowerAdvisor.startPowerHintSession(tidList);
+            if (!mPowerAdvisor.startPowerHintSession(tidList)) {
+                ALOGW("Cannot start power hint session");
+            }
         }
 
         mBootStage = BootStage::FINISHED;