Make it possible to configure synthetic delays through Devtools

tools/telemetry/telemetry/core/browser.py

Index: tools/telemetry/telemetry/core/browser.py
diff --git a/tools/telemetry/telemetry/core/browser.py b/tools/telemetry/telemetry/core/browser.py
index 9659f797df8b8a3f6581f3d13a83bf4177421f91..91eda4fb729dd39d0a9b5d209f0ad5aee16abad8 100644
--- a/tools/telemetry/telemetry/core/browser.py
+++ b/tools/telemetry/telemetry/core/browser.py
@@ -259,6 +259,13 @@ class Browser(object):
   def StopTracing(self):
     return self._browser_backend.StopTracing()
 
+  @property
+  def supports_synthetic_delays(self):
+    return self._browser_backend.supports_synthetic_delays
+
+  def ConfigureSyntheticDelays(self, delays, timeout=10):
+    return self._browser_backend.ConfigureSyntheticDelays(delays, timeout)
+
   def Start(self):
     browser_options = self._browser_backend.browser_options
     if browser_options.clear_sytem_cache_for_browser_and_profile_on_start: