Port part of media.tough_video_cases to TBMv2

tools/perf/benchmarks/media.py

Index: tools/perf/benchmarks/media.py
diff --git a/tools/perf/benchmarks/media.py b/tools/perf/benchmarks/media.py
index c5c6ba613934b033b5f76770000c5d16809565bf..adfe8da02b166f08a0dc2a3dbf818952cd757a60 100644
--- a/tools/perf/benchmarks/media.py
+++ b/tools/perf/benchmarks/media.py
@@ -6,8 +6,10 @@ from core import perf_benchmark
 
 from telemetry import benchmark
 from telemetry.page import legacy_page_test
+from telemetry.timeline import chrome_trace_category_filter
 from telemetry.value import list_of_scalar_values
 from telemetry.value import scalar
+from telemetry.web_perf import timeline_based_measurement
 
 from measurements import media
 import page_sets
@@ -50,6 +52,26 @@ class Media(perf_benchmark.PerfBenchmark):
     return 'media.tough_video_cases'
 
 
+class Media_TBMv2(perf_benchmark.PerfBenchmark):

[charliea (OOO until 10-5), 2017/03/13 16:21:52]

I think MediaToughVideoCasesTBMv2 would be a more idiomatic name

+  """Obtains media metrics using TBMv2. Will eventually replace Media class."""
+  page_set = page_sets.ToughVideoCasesPageSet
+
+  def CreateTimelineBasedMeasurementOptions(self):
+    categories = [
+        # For cpuTimeMetric:

[charliea (OOO until 10-5), 2017/03/13 16:21:52]

nit: you can put this on the same line as 'toplevel', e.g.:

categories = [
    'toplevel',  # Required by cpuTimeMetric
]

+        'toplevel',
+    ]
+    category_filter = chrome_trace_category_filter.ChromeTraceCategoryFilter(
+        ','.join(['-*'] + categories))

[charliea (OOO until 10-5), 2017/03/13 16:21:52]

Yikes: this filter string is confusing.

Looking at it in detail:

','.join(...): join each of the items in the inner list with a comma. Okay, this
isn't bad.

['-*'] + categories: Prepend the list with '-*' as the first item. Presumably
this removes all categories except those explicitly specified. This should be
the same behavior as:

= chrome_trace_category_filter.ChromeTraceCategoryFilter(','.join(categories))

I think the rules for trace category filters are:

- If nothing is specified, use the default filters
- If something is specified, use only that filter

zhenw@chromium.org, can you confirm this?

[Zhen Wang, 2017/03/13 17:30:41]

As far as I remember, this is correct.  I don't really remember why people were
adding "-*" before.

+    options = timeline_based_measurement.Options(category_filter)
+    options.SetTimelineBasedMetrics(['cpuTimeMetric'])
+    return options
+
+  @classmethod
+  def Name(cls):
+    return 'media.tough_video_cases_tbmv2'
+
+
 # crbug.com/565180: Only include cases that don't report time_to_play
 @benchmark.Disabled('android')
 class MediaExtra(perf_benchmark.PerfBenchmark):