[telemetry] Add support for requesting memory dumps via DevTools API

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

 # Copyright 2013 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 import logging
 import pprint
 import re
 import sys
 
 from telemetry.core import exceptions
@@ skipping 287 matching lines @@
 
   @property
   def supports_system_info(self):
     return self.GetSystemInfo() != None
 
   def GetSystemInfo(self):
     if self._system_info_backend is None:
       self._system_info_backend = system_info_backend.SystemInfoBackend(
           self._port)
     return self._system_info_backend.GetSystemInfo()
+
+  @property
+  def supports_memory_dumping(self):
+    return True
+
+  def DumpMemory(self, timeout=web_contents.DEFAULT_WEB_CONTENTS_TIMEOUT):
+    return self.devtools_client.DumpMemory(timeout)