[Telemetry] Fix up desktop_browser_finder on Linux

tools/telemetry/telemetry/internal/backends/chrome/desktop_browser_finder.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.
 """Finds desktop browsers that can be controlled by telemetry."""
 
 import logging
 import os
 import subprocess
 import sys
 
@@ skipping 89 matching lines @@
   return False
 
 def FindAllBrowserTypes(_):
   return [
       'exact',
       'reference',
       'release',
       'release_x64',
       'debug',
       'debug_x64',
+      'stable',
+      'beta',
+      'dev',
       'canary',
       'content-shell-debug',
       'content-shell-debug_x64',
       'content-shell-release',
       'content-shell-release_x64',
       'system']
 
 def FindAllAvailableBrowsers(finder_options, device):
   """Finds all the desktop browsers available on this machine."""
   if not isinstance(device, desktop_device.DesktopDevice):
@@ skipping 96 matching lines @@
       browsers.append(PossibleDesktopBrowser('system', finder_options,
                                              mac_system, None, False,
                                              mac_system_root))
     if path.IsExecutable(mac_reference):
       browsers.append(PossibleDesktopBrowser('reference', finder_options,
                                              mac_reference, None, False,
                                              mac_reference_root))
 
   # Linux specific options.
   if sys.platform.startswith('linux'):
-    # Look for a google-chrome instance.
-    found = False
-    try:
-      with open(os.devnull, 'w') as devnull:
-        found = subprocess.call(['google-chrome', '--version'],
-                                stdout=devnull, stderr=devnull) == 0
-    except OSError:
-      pass
-    if found:
-      browsers.append(PossibleDesktopBrowser('system', finder_options,
-                                             'google-chrome', None, False,
-                                             '/opt/google/chrome'))
+    versions = {
+        'system': ('google-chrome',
+                   os.path.split(os.path.realpath('google-chrome'))[0]),
+        'stable': ('google-chrome-stable', '/opt/google/chrome'),
+        'beta': ('google-chrome-beta', '/opt/google/chrome-beta'),
+        'dev': ('google-chrome-unstable', '/opt/google/chrome-unstable')
+    }
+
+    for version, (name, root) in versions.iteritems():
+      found = False
+      try:
+        with open(os.devnull, 'w') as devnull:
+          found = subprocess.call([name, '--version'],
+                                  stdout=devnull, stderr=devnull) == 0
+      except OSError:
+        pass
+      if found:
+        browsers.append(PossibleDesktopBrowser(version, finder_options, name,
+                                               None, False, root))
     linux_reference_root = os.path.join(reference_build_root, 'chrome_linux')
     linux_reference = os.path.join(linux_reference_root, 'chrome')
     if path.IsExecutable(linux_reference):
       browsers.append(PossibleDesktopBrowser('reference', finder_options,
                                              linux_reference, None, False,
                                              linux_reference_root))
 
   # Win32-specific options.
   if sys.platform.startswith('win'):
     app_paths = (
@@ skipping 16 matching lines @@
     if "--ozone-platform" in arg:
       has_ozone_platform = True
 
   if len(browsers) and not has_x11_display and not has_ozone_platform:
     logging.warning(
       'Found (%s), but you do not have a DISPLAY environment set.' %
       ','.join([b.browser_type for b in browsers]))
     return []
 
   return browsers