Add new onUidProcAdjChanged callback to be consumed by the camera
service.

The camera service needs to know when individual process oom adj scores
are changed in order to address bug #124224342. When two separate
processes are displayed in split screen and focus is switched between
them, both proc states will remain the same while their oom scores
change. This is a problem if both have access to the camera - we want
only one owner of the camera stream at any given time and for the app
in focus to be the one to own it.

This patch adds a new IUidObserver registration level for individual
process oom score changes. In addition a new callback has been added to
IUidObserver to track these changes.

Change-Id: I7695165a205aaf64090016ec6e404b8ad2c33b5d
Bug: 124224342
Test: -- ActivityManagerServiceTest
      -- ActivityManagerProcessStateTest
      -- ActivityManagerFgsBgStartTest
      -- UidObserverControllerTest
      -- NetworkPolicyManagerServiceTest
      -- ShortcutManagerTest2
      -- HintManagerServiceTest
      -- VibrationSettingsTest
      -- CameraEvictionTest#testCamera2AccessCallbackInSplitMode (x100)
diff --git a/services/audiopolicy/service/AudioPolicyService.cpp b/services/audiopolicy/service/AudioPolicyService.cpp
index 9955b6b..f5a37db 100644
--- a/services/audiopolicy/service/AudioPolicyService.cpp
+++ b/services/audiopolicy/service/AudioPolicyService.cpp
@@ -1496,6 +1496,9 @@
     }
 }
 
+void AudioPolicyService::UidPolicy::onUidProcAdjChanged(uid_t uid __unused) {
+}
+
 void AudioPolicyService::UidPolicy::updateOverrideUid(uid_t uid, bool active, bool insert) {
     updateUid(&mOverrideUids, uid, active, ActivityManager::PROCESS_STATE_UNKNOWN, insert);
 }