Add perf tests for starting Chrome with URL

tools/perf/benchmarks/start_with_url.py

Index: tools/perf/benchmarks/start_with_url.py
diff --git a/tools/perf/benchmarks/startup.py b/tools/perf/benchmarks/start_with_url.py
similarity index 55%
copy from tools/perf/benchmarks/startup.py
copy to tools/perf/benchmarks/start_with_url.py
index 1fda6bd638b1d7c1ebb4d2483083bb1eb6b88555..a685e69ca87089da83f6c49b70747d29be24676a 100644
--- a/tools/perf/benchmarks/startup.py
+++ b/tools/perf/benchmarks/start_with_url.py
@@ -6,17 +6,19 @@ from telemetry import test
 from measurements import startup
 
 
-class StartupColdBlankPage(test.Test):
+class StartWithUrlCold(test.Test):
+  """Measure time to start Chrome cold with startup URLs"""
   tag = 'cold'
   test = startup.Startup
-  page_set = 'page_sets/blank_page.json'
+  page_set = 'page_sets/startup_pages.json'
   options = {'cold': True,
              'pageset_repeat_iters': 5}
 
-
-class StartupWarmBlankPage(test.Test):
+class StartWithUrlWarm(test.Test):
+  """Measure time to start Chrome warm with startup URLs"""
   tag = 'warm'
   test = startup.Startup
-  page_set = 'page_sets/blank_page.json'
+  page_set = 'page_sets/startup_pages.json'
   options = {'warm': True,
-             'pageset_repeat_iters': 20}
+             'pageset_repeat_iters': 10}
+