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

tools/perf/benchmarks/speedometer.py

Index: tools/perf/benchmarks/speedometer.py
diff --git a/tools/perf/benchmarks/speedometer.py b/tools/perf/benchmarks/speedometer.py
index edcc2f1ec0fe2da357e9f477e7e92110466512ce..59d1c45eb5d7d5981749f81aec54cccec541ca11 100644
--- a/tools/perf/benchmarks/speedometer.py
+++ b/tools/perf/benchmarks/speedometer.py
@@ -80,6 +80,10 @@ class SpeedometerMeasurement(page_test.PageTest):
 class Speedometer(benchmark.Benchmark):
   test = SpeedometerMeasurement
 
+  @classmethod
+  def Name(cls):
+    return 'speedometer'
+
   def CreatePageSet(self, options):
     ps = page_set.PageSet(
         file_path=os.path.abspath(__file__),