[Telemetry] Explicitly define Name() method for all perf benchmarks

tools/perf/benchmarks/dom_perf.py

Index: tools/perf/benchmarks/dom_perf.py
diff --git a/tools/perf/benchmarks/dom_perf.py b/tools/perf/benchmarks/dom_perf.py
index 87c0bcb7e58dbde2256cd270aa6d7d4ee828bab6..26a0a0d6a451be0bef26e6dc09b267bfed2112a8 100644
--- a/tools/perf/benchmarks/dom_perf.py
+++ b/tools/perf/benchmarks/dom_perf.py
@@ -80,6 +80,10 @@ class DomPerf(benchmark.Benchmark):
   means better performance: Bigger is better!"""
   test = _DomPerfMeasurement
 
+  @classmethod
+  def Name(cls):
+    return 'dom_perf'
+
   def CreatePageSet(self, options):
     dom_perf_dir = os.path.join(util.GetChromiumSrcDir(), 'data', 'dom_perf')
     run_params = [