webrtc: Fix missing port forwarding on CrOS

telemetry/telemetry/core/platform.py

Index: telemetry/telemetry/core/platform.py
diff --git a/telemetry/telemetry/core/platform.py b/telemetry/telemetry/core/platform.py
index 39f151b9fac08e33285a359b3ce73a8b14bcce54..200bf50bf4809b3d2ebde90012ce0d3e26fc60e1 100644
--- a/telemetry/telemetry/core/platform.py
+++ b/telemetry/telemetry/core/platform.py
@@ -10,6 +10,7 @@ from telemetry.core import memory_cache_http_server
 from telemetry.core import network_controller
 from telemetry.core import tracing_controller
 from telemetry.core import util
+from telemetry.internal import forwarders
 from telemetry.internal.platform import (platform_backend as
                                          platform_backend_module)
 
@@ -410,6 +411,15 @@ class Platform(object):
 
     server = memory_cache_http_server.MemoryCacheHTTPServer(paths)
     self.StartLocalServer(server)
+
+    # Requires port forwarding if browser is on remote machine, and
+    # replaces the http_server port number with the one resolved by
+    # remote machine with ssh remote port forwarding.
+    if not self._platform_backend._cri.local:

[nednguyen, 2017/07/18 00:44:58]

This seems very wrong. Not all platform_backend have "._cri" object, so this
will break on non ChromeOS backend.

[cywang, 2017/07/18 09:03:32]

Thanks a lot, I change the section to make it CrOS only.

+      forwarder = self._platform_backend.forwarder_factory.Create(
+          forwarders.PortPair(self.http_server.port, 0),
+          use_remote_port_forwarding=True)
+      self.http_server.port = forwarder.host_port
     return True
 
   def StopAllLocalServers(self):