[telemetry] Implement Forwarder using RNDIS.

tools/telemetry/telemetry/core/backends/chrome/chrome_browser_backend.py

Index: tools/telemetry/telemetry/core/backends/chrome/chrome_browser_backend.py
diff --git a/tools/telemetry/telemetry/core/backends/chrome/chrome_browser_backend.py b/tools/telemetry/telemetry/core/backends/chrome/chrome_browser_backend.py
index 17aaf922686ba8fa55f430b5171ec9ec62f80c50..027572e74589c8d2d0c29e902779023270e68541 100644
--- a/tools/telemetry/telemetry/core/backends/chrome/chrome_browser_backend.py
+++ b/tools/telemetry/telemetry/core/backends/chrome/chrome_browser_backend.py
@@ -71,6 +71,13 @@ class ChromeBrowserBackend(browser_backend.BrowserBackend):
   def extension_dict_backend(self):
     return self._extension_dict_backend
 
+  def GetBrowserStartupArgsForForwarder(self):
+    """Forwarder-specific browser startup args."""
+    return wpr_server.GetChromeFlags(
+          self.WEBPAGEREPLAY_HOST,
+          self.webpagereplay_remote_http_port,
+          self.webpagereplay_remote_https_port)
+
   def GetBrowserStartupArgs(self):
     args = []
     args.extend(self.options.extra_browser_args)
@@ -78,10 +85,7 @@ class ChromeBrowserBackend(browser_backend.BrowserBackend):
     args.append('--metrics-recording-only')
     args.append('--no-first-run')
     if self.options.wpr_mode != wpr_modes.WPR_OFF:
-      args.extend(wpr_server.GetChromeFlags(
-          self.WEBPAGEREPLAY_HOST,
-          self.webpagereplay_remote_http_port,
-          self.webpagereplay_remote_https_port))
+      args.extend(self.GetBrowserStartupArgsForForwarder())
     args.extend(user_agent.GetChromeUserAgentArgumentFromType(
         self.options.browser_user_agent_type))