Add WebView Multiprocess startup benchmark.

tools/perf/benchmarks/system_health.py

Index: tools/perf/benchmarks/system_health.py
diff --git a/tools/perf/benchmarks/system_health.py b/tools/perf/benchmarks/system_health.py
index 2d80785a99da3ac35da7d034cc2eb86f70e8efc2..e32faf83f64f1953788881f059ad9ece1ee2954b 100644
--- a/tools/perf/benchmarks/system_health.py
+++ b/tools/perf/benchmarks/system_health.py
@@ -91,6 +91,7 @@ class WebviewStartupSystemHealthBenchmark(perf_benchmark.PerfBenchmark):
   benchmark.
   """
   page_set = page_sets.BlankPageSet
+  options = {'pageset_repeat': 10}

[hush (inactive), 2016/09/02 18:48:02]

does the blank page set only contain one blank page?

I feel that the repeat of 10 is too few though...

[mikecase (-- gone --), 2016/09/06 16:40:28]

Yes, only contains a blank page so the test is very fast. And I up'ed the
repeats to 20.

 
   def CreateTimelineBasedMeasurementOptions(self):
     options = timeline_based_measurement.Options()
@@ -107,3 +108,21 @@ class WebviewStartupSystemHealthBenchmark(perf_benchmark.PerfBenchmark):
   @classmethod
   def Name(cls):
     return 'system_health.webview_startup'
+

[hush (inactive), 2016/09/02 18:48:02]

nit: remove this blank line

[petrcermak, 2016/09/05 12:45:51]

No, don't remove it. There should be two blank lines between all top-level
definitions.

[mikecase (-- gone --), 2016/09/06 16:40:28]

Done

+
+@benchmark.Enabled('android-webview')
+class WebviewMultiprocessStartupSystemHealthBenchmark(
+    WebviewStartupSystemHealthBenchmark):
+  """Webview multiprocess startup time benchmark
+
+  Benchmark that measures how long WebView takes to start up
+  and load a blank page with multiprocess enabled.
+  """
+
+  def SetExtraBrowserOptions(self, options):
+    options.AppendExtraBrowserArgs(
+        ['--webview-sandboxed-renderer'])
+
+  @classmethod
+  def Name(cls):
+    return 'system_health.webview_startup_multiprocess'