[telemetry] Implement Forwarder using RNDIS.

tools/telemetry/telemetry/core/chrome/android_browser_backend.py

Index: tools/telemetry/telemetry/core/chrome/android_browser_backend.py
diff --git a/tools/telemetry/telemetry/core/chrome/android_browser_backend.py b/tools/telemetry/telemetry/core/chrome/android_browser_backend.py
index 34aa933ee18e62871f1261e8fb2cf83e037c7059..1aa7f5b90ca4bf7e523b63e0f8a7b02418fe56b5 100644
--- a/tools/telemetry/telemetry/core/chrome/android_browser_backend.py
+++ b/tools/telemetry/telemetry/core/chrome/android_browser_backend.py
@@ -171,6 +171,8 @@ class AndroidBrowserBackend(chrome_browser_backend.ChromeBrowserBackend):
       if options.profile_dir:
         self._backend_settings.PushProfile(options.profile_dir)
 
+    self._root_enabled = self._adb.IsRootEnabled()
+
     # Set up the command line.
     self._saved_cmdline = ''.join(self._adb.Adb().GetProtectedFileContents(
         self._backend_settings.cmdline_file) or [])
@@ -300,5 +302,25 @@ class AndroidBrowserBackend(chrome_browser_backend.ChromeBrowserBackend):
                                        stdout=subprocess.PIPE).communicate()[0])
     return ret
 
+  def AddReplayServerOptions(self, options):
+    """Override. Only add --no-dns_forwarding if not using RNDIS."""
+    if not self._root_enabled:
+      options.append('--no-dns_forwarding')
+
+  def GetBrowserStartupArgsForForwarder(self):
+    """Override. Remove --host-resolver-rules when using RNDIS."""
+    args = super(AndroidBrowserBackend,
+                 self).GetBrowserStartupArgsForForwarder()
+    if self._root_enabled:
+      args = [arg for arg in args
+              if not arg.startswith('--host-resolver-rules')]
+    return args
+
   def CreateForwarder(self, *port_pairs):
+    if self._root_enabled:
+      forwarder = adb_commands.RndisForwarderWithRoot(self._adb, *port_pairs)
+      self.WEBPAGEREPLAY_HOST = forwarder.host_ip
+      return forwarder
+    sys.stderr.write('WARNING: Using the old forwarder. '
+                     'Execute adb root to enable RNDIS.\n')
     return adb_commands.Forwarder(self._adb, *port_pairs)