tools_webrtc dir converted to py3 + top level PRESUBMIT script

Bug: webrtc:13607
Change-Id: Ib018e43ea977cc24dd71048e68e3343741f7f31b
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/249083
Reviewed-by: Mirko Bonadei <mbonadei@webrtc.org>
Reviewed-by: Harald Alvestrand <hta@webrtc.org>
Reviewed-by: Jeremy Leconte <jleconte@google.com>
Commit-Queue: Christoffer Jansson <jansson@google.com>
Cr-Commit-Position: refs/heads/main@{#35953}
diff --git a/tools_webrtc/network_emulator/config.py b/tools_webrtc/network_emulator/config.py
index c1d3eaf..9a18bdc 100644
--- a/tools_webrtc/network_emulator/config.py
+++ b/tools_webrtc/network_emulator/config.py
@@ -1,4 +1,5 @@
-#!/usr/bin/env python
+#!/usr/bin/env vpython3
+
 #  Copyright (c) 2012 The WebRTC project authors. All Rights Reserved.
 #
 #  Use of this source code is governed by a BSD-style license
@@ -9,28 +10,27 @@
 """Configuration class for network emulation."""
 
 
-class ConnectionConfig(object):
-    """Configuration containing the characteristics of a network connection."""
+class ConnectionConfig:
+  """Configuration containing the characteristics of a network connection."""
 
-    def __init__(self, num, name, receive_bw_kbps, send_bw_kbps, delay_ms,
-                 packet_loss_percent, queue_slots):
-        self.num = num
-        self.name = name
-        self.receive_bw_kbps = receive_bw_kbps
-        self.send_bw_kbps = send_bw_kbps
-        self.delay_ms = delay_ms
-        self.packet_loss_percent = packet_loss_percent
-        self.queue_slots = queue_slots
+  def __init__(self, num, name, receive_bw_kbps, send_bw_kbps, delay_ms,
+               packet_loss_percent, queue_slots):
+    self.num = num
+    self.name = name
+    self.receive_bw_kbps = receive_bw_kbps
+    self.send_bw_kbps = send_bw_kbps
+    self.delay_ms = delay_ms
+    self.packet_loss_percent = packet_loss_percent
+    self.queue_slots = queue_slots
 
-    def __str__(self):
-        """String representing the configuration.
+  def __str__(self):
+    """String representing the configuration.
 
     Returns:
         A string formatted and padded like this example:
     12 Name                       375 kbps   375 kbps   10   145 ms  0.1 %
     """
-        left_aligned_name = self.name.ljust(24, ' ')
-        return '%2s %24s %5s kbps %5s kbps %4s %5s ms  %3s %%' % (
-            self.num, left_aligned_name, self.receive_bw_kbps,
-            self.send_bw_kbps, self.queue_slots, self.delay_ms,
-            self.packet_loss_percent)
+    left_aligned_name = self.name.ljust(24, ' ')
+    return '%2s %24s %5s kbps %5s kbps %4s %5s ms  %3s %%' % (
+        self.num, left_aligned_name, self.receive_bw_kbps, self.send_bw_kbps,
+        self.queue_slots, self.delay_ms, self.packet_loss_percent)