Enable installing test CA on Android & add test for it

telemetry/telemetry/internal/backends/chrome/chrome_browser_backend.py

Index: telemetry/telemetry/internal/backends/chrome/chrome_browser_backend.py
diff --git a/telemetry/telemetry/internal/backends/chrome/chrome_browser_backend.py b/telemetry/telemetry/internal/backends/chrome/chrome_browser_backend.py
index 908239d798e35054745a91fcab9a802e15298df9..ecd64b6fbd92363a34095632b200c023357a47fb 100644
--- a/telemetry/telemetry/internal/backends/chrome/chrome_browser_backend.py
+++ b/telemetry/telemetry/internal/backends/chrome/chrome_browser_backend.py
@@ -127,10 +127,18 @@ class ChromeBrowserBackend(browser_backend.BrowserBackend):
       return []
     proxy_port = network_backend.forwarder.port_pair.remote_port
     replay_args.append('--proxy-server=socks://localhost:%s' % proxy_port)
+
     if not network_backend.is_test_ca_installed:
       # Ignore certificate errors if the platform backend has not created
       # and installed a root certificate.
       replay_args.append('--ignore-certificate-errors')
+    else:
+      # For now, also use '--ignore-certificate-errors' even if test ca is
+      # installed.
+      # TODO(nedn, xunjieli): remove this flag if test ca is installed
+      # (crbug.com/716084)
+      replay_args.append('--ignore-certificate-errors')
+
     return replay_args
 
   def HasBrowserFinishedLaunching(self):