Fix MetricsCollectorTest.ResponsivenessMetric

ukm::UkmRecorder::GetNewSourceID may return negative ids.

Bug: 833028
Change-Id: If4f8c3668524baa791b9b3895f95f19d135664b3
Reviewed-on: https://chromium-review.googlesource.com/1020669
Commit-Queue: Chris Hamilton <chrisha@chromium.org>
Reviewed-by: Chris Hamilton <chrisha@chromium.org>
Cr-Commit-Position: refs/heads/master@{#553000}

services/resource_coordinator/observers/metrics_collector.cc

@@ -217,14 +217,14 @@ bool MetricsCollector::IsCollectingCPUUsageForUkm(
     const CoordinationUnitID& page_cu_id) {
   const UkmCollectionState& state = ukm_collection_state_map_[page_cu_id];
 
-  return state.ukm_source_id > ukm::kInvalidSourceId &&
+  return state.ukm_source_id != ukm::kInvalidSourceId &&
          state.num_cpu_usage_measurements < max_ukm_cpu_usage_measurements_;
 }
 
 bool MetricsCollector::IsCollectingExpectedQueueingTimeForUkm(
     const CoordinationUnitID& page_cu_id) {
   UkmCollectionState& state = ukm_collection_state_map_[page_cu_id];
-  return state.ukm_source_id > ukm::kInvalidSourceId &&
+  return state.ukm_source_id != ukm::kInvalidSourceId &&
          ++state.num_unreported_eqt_measurements >= frequency_ukm_eqt_reported_;
 }
 

services/resource_coordinator/observers/metrics_collector_unittest.cc

@@ -346,7 +346,7 @@ TEST_F(MAYBE_MetricsCollectorTest,
 }
 
 // Flaky test: https://crbug.com/833028
-TEST_F(MAYBE_MetricsCollectorTest, DISABLED_ResponsivenessMetric) {
+TEST_F(MAYBE_MetricsCollectorTest, ResponsivenessMetric) {
   auto page_cu = CreateCoordinationUnit<PageCoordinationUnitImpl>();
   coordination_unit_manager().OnCoordinationUnitCreated(page_cu.get());
   auto process_cu = CreateCoordinationUnit<ProcessCoordinationUnitImpl>();