Enable chrome tracing in the webview_startup benchmark test

Bug: 1010364
Change-Id: I3e96e02bc1067afd3d33ab5873cf6ec0a2f17756
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1864468
Commit-Queue: Oksana Zhuravlova <oksamyt@chromium.org>
Reviewed-by: Juan Antonio Navarro Pérez <perezju@chromium.org>
Cr-Commit-Position: refs/heads/master@{#708728}

tools/perf/benchmarks/system_health.py

@@ -157,9 +157,7 @@ class WebviewStartupSystemHealthBenchmark(perf_benchmark.PerfBenchmark):
   """Webview startup time benchmark
 
   Benchmark that measures how long WebView takes to start up
-  and load a blank page. Since thie metric only requires the trace
-  markers recorded in atrace, Chrome tracing is not enabled for this
-  benchmark.
+  and load a blank page.
   """
   options = {'pageset_repeat': 20}
   SUPPORTED_PLATFORMS = [story.expectations.ANDROID_WEBVIEW]
@@ -168,10 +166,12 @@ class WebviewStartupSystemHealthBenchmark(perf_benchmark.PerfBenchmark):
     return page_sets.SystemHealthBlankStorySet()
 
   def CreateCoreTimelineBasedMeasurementOptions(self):
-    options = timeline_based_measurement.Options()
+    cat_filter = chrome_trace_category_filter.ChromeTraceCategoryFilter(
+        filter_string='startup')
+    options = timeline_based_measurement.Options(cat_filter)
     options.SetTimelineBasedMetrics(['webviewStartupMetric'])
     options.config.enable_atrace_trace = True
-    options.config.enable_chrome_trace = False
+    options.config.enable_chrome_trace = True
     options.config.atrace_config.app_name = 'org.chromium.webview_shell'
     return options