[android] Handle non-existent gtest XML result file.

Bug: 765673
Change-Id: Icb0dcc89e2898f7a03c6558aa4ff07eef9508ac6
Reviewed-on: https://chromium-review.googlesource.com/668796
Reviewed-by: Benjamin Pastene <bpastene@chromium.org>
Commit-Queue: John Budorick <jbudorick@chromium.org>
Cr-Commit-Position: refs/heads/master@{#502382}

build/android/pylib/gtest/gtest_test_instance.py

@@ -207,10 +207,11 @@ def handle_possibly_unknown_test():
 def ParseGTestXML(xml_content):
   """Parse gtest XML result."""
   results = []
+  if not xml_content:
+    return results
 
   html = HTMLParser.HTMLParser()
 
-  # TODO(jbudorick): Unclear how this handles crashes.
   testsuites = xml.etree.ElementTree.fromstring(xml_content)
   for testsuite in testsuites:
     suite_name = testsuite.attrib['name']

build/android/pylib/gtest/gtest_test_instance_test.py

@@ -177,6 +177,10 @@ def testParseGTestOutput_deathTestCrashOk(self):
     self.assertEquals(1, actual[0].GetDuration())
     self.assertEquals(base_test_result.ResultType.PASS, actual[0].GetType())
 
+  def testParseGTestXML_none(self):
+    actual = gtest_test_instance.ParseGTestXML(None)
+    self.assertEquals([], actual)
+
   def testConvertTestFilterFile_commentsAndBlankLines(self):
     input_lines = [
       'positive1',

build/android/pylib/local/device/local_device_gtest_run.py

@@ -421,9 +421,16 @@ def _RunTest(self, device, test):
             timeout=timeout, retries=0)
 
       if self._test_instance.enable_xml_result_parsing:
-        gtest_xml = device.ReadFile(
-            device_tmp_results_file.name,
-            as_root=True)
+        try:
+          gtest_xml = device.ReadFile(
+              device_tmp_results_file.name,
+              as_root=True)
+        except device_errors.CommandFailedError as e:
+          logging.warning(
+              'Failed to pull gtest results XML file %s: %s',
+              device_tmp_results_file.name,
+              str(e))
+          gtest_xml = None
 
     for s in self._servers[str(device)]:
       s.Reset()