SurfaceStats / Telemetry: calculate FPS in different frame buckets.

tools/perf/measurements/smoothness.py

Index: tools/perf/measurements/smoothness.py
diff --git a/tools/perf/measurements/smoothness.py b/tools/perf/measurements/smoothness.py
index 80b7cd6307ccfaf12f1718c0f9c98d3d20be6ef2..b875127d9783e515654e75feda70e426bd2d8560 100644
--- a/tools/perf/measurements/smoothness.py
+++ b/tools/perf/measurements/smoothness.py
@@ -10,9 +10,9 @@ class DidNotScrollException(page_measurement.MeasurementFailure):
     super(DidNotScrollException, self).__init__('Page did not scroll')
 
 class MissingDisplayFrameRate(page_measurement.MeasurementFailure):
-  def __init__(self):
+  def __init__(self, name):
     super(MissingDisplayFrameRate, self).__init__(
-        'Missing display frame rate metrics')
+        'Missing display frame rate metrics: ' + name)
 
 def DivideIfPossibleOrZero(numerator, denominator):
   if denominator == 0:
@@ -226,6 +226,6 @@ class Smoothness(page_measurement.PageMeasurement):
 
     if tab.browser.platform.IsRawDisplayFrameRateSupported():
       for r in tab.browser.platform.GetRawDisplayFrameRateMeasurements():
-        if not r.value:
-          raise MissingDisplayFrameRate()
+        if r.value is None:
+          raise MissingDisplayFrameRate(r.name)
         results.Add(r.name, r.unit, r.value)