Add comments and asserts that didn't merge with PR 5059 (#5063)

* Add different defaults for when RC fetch failed

* Add changelog entry

* Format

* Add throttled case to isLastFetchFailed check

* Add rc fetch failed defaults for cpu and memory capturing frequency

* Address comments

Author: mrober

firebase-perf/src/main/java/com/google/firebase/perf/config/ConfigurationConstants.java

@@ -232,6 +232,7 @@ protected Long getDefault() {
 
     @Override
     protected Long getDefaultOnRcFetchFail() {
+      // Increase the typical default by factor of 3.
       return getDefault() * 3;
     }
 
@@ -313,6 +314,7 @@ protected Long getDefault() {
 
     @Override
     protected Long getDefaultOnRcFetchFail() {
+      // Increase the typical default by factor of 3.
       return getDefault() * 3;
     }
 

firebase-perf/src/test/java/com/google/firebase/perf/config/ConfigurationConstantsTest.java

@@ -155,6 +155,7 @@ public void getInstance_TraceSamplingRate_validateConstants() {
     TraceSamplingRate configFlag = TraceSamplingRate.getInstance();
 
     assertThat(configFlag.getDefault()).isEqualTo(1.00);
+    assertThat(configFlag.getDefaultOnRcFetchFail()).isEqualTo(0.01);
     assertThat(configFlag.getDeviceCacheFlag())
         .isEqualTo("com.google.firebase.perf.TraceSamplingRate");
     assertThat(configFlag.getRemoteConfigFlag()).isEqualTo("fpr_vc_trace_sampling_rate");
@@ -166,6 +167,7 @@ public void getInstance_NetworkRequestSamplingRate_validateConstants() {
     NetworkRequestSamplingRate configFlag = NetworkRequestSamplingRate.getInstance();
 
     assertThat(configFlag.getDefault()).isEqualTo(1.00);
+    assertThat(configFlag.getDefaultOnRcFetchFail()).isEqualTo(0.01);
     assertThat(configFlag.getDeviceCacheFlag())
         .isEqualTo("com.google.firebase.perf.NetworkRequestSamplingRate");
     assertThat(configFlag.getRemoteConfigFlag()).isEqualTo("fpr_vc_network_request_sampling_rate");
@@ -177,6 +179,7 @@ public void getInstance_SessionsSamplingRate_validateConstants() {
     SessionsSamplingRate configFlag = SessionsSamplingRate.getInstance();
 
     assertThat(configFlag.getDefault()).isEqualTo(0.01);
+    assertThat(configFlag.getDefaultOnRcFetchFail()).isEqualTo(0.0001);
     assertThat(configFlag.getDeviceCacheFlag())
         .isEqualTo("com.google.firebase.perf.SessionSamplingRate");
     assertThat(configFlag.getRemoteConfigFlag()).isEqualTo("fpr_vc_session_sampling_rate");