Add a module for tracking categories that metrics depend on.

tools/perf/benchmarks/system_health.py

Index: tools/perf/benchmarks/system_health.py
diff --git a/tools/perf/benchmarks/system_health.py b/tools/perf/benchmarks/system_health.py
index 3c66450b4934c1f34adcf24e2e5f5d91c5b30efd..e8e445883b0d8a7d8b787a0551950160f50fe6b2 100644
--- a/tools/perf/benchmarks/system_health.py
+++ b/tools/perf/benchmarks/system_health.py
@@ -4,7 +4,7 @@
 
 import re
 
-from benchmarks import page_cycler_v2
+from benchmarks import metric_dependencies
 
 from core import perf_benchmark
 
@@ -41,10 +41,11 @@ class _CommonSystemHealthBenchmark(perf_benchmark.PerfBenchmark):
     options.config.enable_chrome_trace = True
     options.SetTimelineBasedMetrics([
         'clockSyncLatencyMetric',
+        'loadingMetric',
         'powerMetric',
         'tracingMetric'
     ])
-    page_cycler_v2.AugmentOptionsForLoadingMetrics(options)
+    metric_dependencies.AugmentOptionsForMetrics(options, ['loadingMetric'])
     return options
 
   def CreateStorySet(self, options):