[Fireperf][AASA] Experiment time-to-initial-display 3 (#4457)

* revert uptime and add androidx ProcessLifecycleOwner

* comments and style improvements

* gjf

* counters and attributes

* fix background attribute

* names

* reorganized subtraces

* downgrade androidx.lifecycle:lifecycle-process for firebase compatibility

* predraw foq and cleaner code

* fix CI tests

* fix test

* add comments

* onDrawCount and systemBackgroundCheck

* fix typo

* fix tests

* fix bug with experiment not sending under API 24

Author: leotianlizhan

firebase-perf/firebase-perf.gradle

@@ -109,6 +109,7 @@ dependencies {
     implementation "com.google.android.gms:play-services-tasks:18.0.1"
     implementation 'androidx.appcompat:appcompat:1.2.0'
     implementation "androidx.annotation:annotation:1.1.0"
+    implementation "androidx.lifecycle:lifecycle-process:2.3.1"
 
     // 3rd Party Deps
     implementation 'com.squareup.okhttp3:okhttp:3.12.1'