Fix cros telemetry bustage.

tools/telemetry/telemetry/core/chrome/cros_browser_backend.py

Index: tools/telemetry/telemetry/core/chrome/cros_browser_backend.py
diff --git a/tools/telemetry/telemetry/core/chrome/cros_browser_backend.py b/tools/telemetry/telemetry/core/chrome/cros_browser_backend.py
index c5dede5b00b469c4a65ba8f37c35f71a808ac053..0f73add31194aa5a1a0a51c6a0e348d7ad444d56 100644
--- a/tools/telemetry/telemetry/core/chrome/cros_browser_backend.py
+++ b/tools/telemetry/telemetry/core/chrome/cros_browser_backend.py
@@ -140,14 +140,14 @@ class CrOSBrowserBackend(chrome_browser_backend.ChromeBrowserBackend):
   @property
   def pid(self):
     result = self._GetChromeProcess()
-    if 'pid' in result:
+    if result and 'pid' in result:
       return result['pid']
     return None
 
   @property
   def browser_directory(self):
     result = self._GetChromeProcess()
-    if 'path' in result:
+    if result and 'path' in result:
       return result['path']
     return None