[telemetry] Add a version of v8.todomvc that runs using ignition

tools/perf/benchmarks/v8.py

Index: tools/perf/benchmarks/v8.py
diff --git a/tools/perf/benchmarks/v8.py b/tools/perf/benchmarks/v8.py
index 92ad47e446af11f3b407fc1607024a7b4de63519..cc894db81e6d8c48a64c372fe3b30c6cfdab38a1 100644
--- a/tools/perf/benchmarks/v8.py
+++ b/tools/perf/benchmarks/v8.py
@@ -138,6 +138,38 @@ class V8TodoMVC(perf_benchmark.PerfBenchmark):
     return True
 
 
+class V8TodoMVCIgnition(perf_benchmark.PerfBenchmark):
+  """Measures V8 Execution metrics on the TodoMVC examples using ignition."""
+  page_set = page_sets.TodoMVCPageSet
+
+  def SetExtraBrowserOptions(self, options):
+    existing_js_flags = []
+    for extra_arg in options.extra_browser_args:
+      if extra_arg.startswith('--js-flags='):
+        existing_js_flags.extend(shlex.split(extra_arg[len('--js-flags='):]))
+    options.AppendExtraBrowserArgs([
+        # This overrides any existing --js-flags, hence we have to include the
+        # previous flags as well.
+        '--js-flags="--ignition %s"' % (' '.join(existing_js_flags))
+    ])
+
+  def CreateTimelineBasedMeasurementOptions(self):
+    category_filter = tracing_category_filter.CreateMinimalOverheadFilter()
+    category_filter.AddIncludedCategory('v8')
+    category_filter.AddIncludedCategory('blink.console')
+    options = timeline_based_measurement.Options(category_filter)
+    options.SetLegacyTimelineBasedMetrics([v8_execution.V8ExecutionMetric()])

[rmcilroy, 2016/03/17 15:25:37]

I'm not sure these will capture any compile time for ignition since they look
for V8.CompileFullCode explicitly. I'll land an equivalent trace event for
ignition, but we'll need to update these metrics too before we get any results.

+    return options
+
+  @classmethod
+  def Name(cls):
+    return 'v8.todomvc-ignition'
+
+  @classmethod
+  def ShouldTearDownStateAfterEachStoryRun(cls):

[Sami, 2016/03/15 12:13:55]

Like we discussed this should probably use the deprecated-but-working restart
API (i.e., needs_browser_restart_after_each_page=True) since
https://crrev.com/43f84917812c614b2a38e8e27064c6873ca6cdb0 got reverted.
MemoryInfra also has this bug (crbug.com/594952).

Zhen, can you suggest a way to use the old API from here?

[jochen (gone - plz use gerrit), 2016/03/15 12:19:08]

needs_browser_restart_after_each_page only works with pre-timeline based tests.

For timeline based measurements, you'd have to specify a startup-url (which
works), but then timeline based measurements crashes, because it starts the
tracing controller before the story is run, and expects it to stay active (which
it doesn't when the entire browser is swapped).

[Zhen Wang, 2016/03/15 15:48:44]

This API should not be used. What are the use cases here? Please continue the
discussion in https://bugs.chromium.org/p/chromium/issues/detail?id=594952.
Thanks for finding this. :)

+    return True
+
+
 # Disabled on reference builds because they don't support the new
 # Tracing.requestMemoryDump DevTools API. See http://crbug.com/540022.
 @benchmark.Disabled('reference', 'android')  # crbug.com/579546