Remove static for experiment accessors in UKMRecorderImpl

Unittests rely on ScopedFeatureList which does not work
because of these static values.

Bug: 1166714
Change-Id: Ie3b0ff8beac1efa2398c68e77725ff69fce9cc2a
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2627405
Commit-Queue: Olivier Robin <olivierrobin@chromium.org>
Reviewed-by: Alexei Svitkine <asvitkine@chromium.org>
Cr-Commit-Position: refs/heads/master@{#844187}

components/ukm/ukm_recorder_impl.cc

@@ -55,34 +55,6 @@ bool IsWhitelistedSourceId(SourceId source_id) {
          GetSourceIdType(source_id) == SourceIdType::PAYMENT_APP_ID;
 }
 
-// Gets the maximum number of Sources we'll keep in memory before discarding any
-// new ones being added.
-size_t GetMaxSources() {
-  constexpr size_t kDefaultMaxSources = 500;
-  static auto value = static_cast<size_t>(base::GetFieldTrialParamByFeatureAsInt(
-      kUkmFeature, "MaxSources", kDefaultMaxSources));
-  return value;
-}
-
-// Gets the maximum number of Sources we can keep in memory at the end of the
-// current reporting cycle that will stay accessible in the next reporting
-// interval.
-size_t GetMaxKeptSources() {
-  constexpr size_t kDefaultMaxKeptSources = 100;
-  static auto value = static_cast<size_t>(base::GetFieldTrialParamByFeatureAsInt(
-      kUkmFeature, "MaxKeptSources", kDefaultMaxKeptSources));
-  return value;
-}
-
-// Gets the maximum number of Entries we'll keep in memory before discarding any
-// new ones being added.
-size_t GetMaxEntries() {
-  constexpr size_t kDefaultMaxEntries = 5000;
-  static auto value = static_cast<size_t>(base::GetFieldTrialParamByFeatureAsInt(
-      kUkmFeature, "MaxEntries", kDefaultMaxEntries));
-  return value;
-}
-
 // Returns whether |url| has one of the schemes supported for logging to UKM.
 // URLs with other schemes will not be logged.
 bool HasSupportedScheme(const GURL& url) {
@@ -218,8 +190,16 @@ bool HasUnknownMetrics(const builders::DecodeMap& decode_map,
 }  // namespace
 
 UkmRecorderImpl::UkmRecorderImpl()
-    : recording_enabled_(false),
-      sampling_seed_(static_cast<uint32_t>(base::RandUint64())) {}
+    : sampling_seed_(static_cast<uint32_t>(base::RandUint64())) {
+  max_sources_ = static_cast<size_t>(base::GetFieldTrialParamByFeatureAsInt(
+      kUkmFeature, "MaxSources", max_sources_));
+  max_kept_sources_ =
+      static_cast<size_t>(base::GetFieldTrialParamByFeatureAsInt(
+          kUkmFeature, "MaxKeptSources", max_kept_sources_));
+  max_entries_ = static_cast<size_t>(base::GetFieldTrialParamByFeatureAsInt(
+      kUkmFeature, "MaxEntries", max_entries_));
+}
+
 UkmRecorderImpl::~UkmRecorderImpl() = default;
 
 // static
@@ -523,7 +503,7 @@ void UkmRecorderImpl::StoreRecordingsInReport(Report* report) {
 
   // Defer at most GetMaxKeptSources() sources to the next report,
   // prioritizing most recently created ones.
-  int pruned_sources_age = PruneOldSources(GetMaxKeptSources());
+  int pruned_sources_age = PruneOldSources(max_kept_sources_);
   // Record how old the newest truncated source is.
   source_counts_proto->set_pruned_sources_age_seconds(pruned_sources_age);
 
@@ -671,7 +651,7 @@ bool UkmRecorderImpl::ShouldRecordUrl(SourceId source_id,
     return false;
   }
 
-  if (recordings_.sources.size() >= GetMaxSources()) {
+  if (recordings_.sources.size() >= max_sources_) {
     RecordDroppedSource(DroppedDataReason::MAX_HIT);
     return false;
   }
@@ -770,7 +750,7 @@ void UkmRecorderImpl::AddEntry(mojom::UkmEntryPtr entry) {
     }
   }
 
-  if (recordings_.entries.size() >= GetMaxEntries()) {
+  if (recordings_.entries.size() >= max_entries_) {
     RecordDroppedEntry(entry->event_hash, DroppedDataReason::MAX_HIT);
     event_aggregate.dropped_due_to_limits++;
     for (auto& metric : entry->metrics)

components/ukm/ukm_recorder_impl.h

@@ -274,6 +274,19 @@ class COMPONENT_EXPORT(UKM_RECORDER) UkmRecorderImpl : public UkmRecorder {
   };
   Recordings recordings_;
 
+  // The maximum number of Sources we'll keep in memory before discarding any
+  // new ones being added.
+  size_t max_sources_ = 500;
+
+  // The maximum number of Sources we can keep in memory at the end of the
+  // current reporting cycle that will stay accessible in the next reporting
+  // interval.
+  size_t max_kept_sources_ = 100;
+
+  // The maximum number of Entries we'll keep in memory before discarding any
+  // new ones being added.
+  size_t max_entries_ = 5000;
+
   SEQUENCE_CHECKER(sequence_checker_);
 };