[telemetry] Only run reference builds on desktop.

tools/telemetry/telemetry/test_runner.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.
 
 """Parses the command line, discovers the appropriate tests, and runs them.
 
 Handles test configuration, but all the logic for
 actually running the test is in Test and PageRunner."""
 
 import hashlib
@@ skipping 71 matching lines @@
     if not args.positional_args:
       args.tests = _Tests()
     elif len(args.positional_args) == 1:
       args.tests = _MatchTestName(args.positional_args[0], exact_matches=False)
     else:
       parser.error('Must provide at most one test name.')
 
   def Run(self, args):
     if args.json_output_file:
       possible_browser = browser_finder.FindBrowser(args)
-      args.browser_type = 'reference'
-      possible_reference_browser = browser_finder.FindBrowser(args)
+      if args.browser_type in (
+          'exact', 'release', 'release_x64', 'debug', 'debug_x64', 'canary'):
+        args.browser_type = 'reference'
+        possible_reference_browser = browser_finder.FindBrowser(args)
+      else:
+        possible_reference_browser = None
       with open(args.json_output_file, 'w') as f:
         f.write(_GetJsonTestList(possible_browser, possible_reference_browser,
                                  args.tests, args.num_shards))
     else:
       _PrintTestList(args.tests)
     return 0
 
 
 class Run(command_line.OptparseCommand):
   """Run one or more tests (default)"""
@@ skipping 265 matching lines @@
 
   # Parse and run the command.
   parser = command.CreateParser()
   command.AddCommandLineArgs(parser)
   options, args = parser.parse_args()
   if commands:
     args = args[1:]
   options.positional_args = args
   command.ProcessCommandLineArgs(parser, options)
   return command().Run(options)