Expanded poweradvisor to handle adpf hint sessions

This patch exposes several new methods from the PowerAdvisor to enable SurfaceFlinger to set up hint sessions and send updates for the desired and actual durations.

Bug: 195990840
Test: make;
manual testing

Change-Id: Ice16c09309be81d9d661dfb818882cfea8e4d4aa
diff --git a/services/surfaceflinger/SurfaceFlinger.cpp b/services/surfaceflinger/SurfaceFlinger.cpp
index 54bcd15..88a1cba 100644
--- a/services/surfaceflinger/SurfaceFlinger.cpp
+++ b/services/surfaceflinger/SurfaceFlinger.cpp
@@ -709,6 +709,7 @@
     ALOGI("Boot is finished (%ld ms)", long(ns2ms(duration)) );
 
     mFlagManager = std::make_unique<android::FlagManager>();
+    mPowerAdvisor.enablePowerHint(mFlagManager->use_adpf_cpu_hint());
     mFrameTracer->initialize();
     mFrameTimeline->onBootFinished();