[Telemetry] Move WPR life cycle from browser to platform

tools/telemetry/telemetry/internal/forwarders/__init__.py

Index: tools/telemetry/telemetry/internal/forwarders/__init__.py
diff --git a/tools/telemetry/telemetry/internal/forwarders/__init__.py b/tools/telemetry/telemetry/internal/forwarders/__init__.py
index e05fb3b558b10e38be479bc4d25c90933a8df000..ecaa4a5410e87b9ed88fb8a67716d649f9119d82 100644
--- a/tools/telemetry/telemetry/internal/forwarders/__init__.py
+++ b/tools/telemetry/telemetry/internal/forwarders/__init__.py
@@ -6,7 +6,27 @@ import collections
 
 
 PortPair = collections.namedtuple('PortPair', ['local_port', 'remote_port'])
-PortPairs = collections.namedtuple('PortPairs', ['http', 'https', 'dns'])
+PortSet = collections.namedtuple('PortSet', ['http', 'https', 'dns'])
+
+
+class PortPairs(collections.namedtuple('PortPairs', ['http', 'https', 'dns'])):
+  __slots__ = ()
+
+  @classmethod
+  def Make(cls, http, https, dns=None):
+    """Allow to easily create a PortPairs object from regular tuple pairs."""
+    return cls(http=PortPair(*http), https=PortPair(*https),
+               dns=PortPair(*dns) if dns else None)
+
+  @property
+  def local_ports(self):
+    ports = [pair.local_port if pair is not None else None for pair in self]
+    return PortSet(*ports)
+
+  @property
+  def remote_ports(self):
+    ports = [pair.remote_port if pair is not None else None for pair in self]
+    return PortSet(*ports)
 
 
 class ForwarderFactory(object):