Record screenshots on failures on swarming bots.

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

Index: build/android/pylib/local/device/local_device_instrumentation_test_run.py
diff --git a/build/android/pylib/local/device/local_device_instrumentation_test_run.py b/build/android/pylib/local/device/local_device_instrumentation_test_run.py
index 7bfe3f5974efed2439e332afc0cd94f7ccd968ab..c23aa5c17f351422244be69a36f0d0c5245948f4 100644
--- a/build/android/pylib/local/device/local_device_instrumentation_test_run.py
+++ b/build/android/pylib/local/device/local_device_instrumentation_test_run.py
@@ -370,22 +370,29 @@ class LocalDeviceInstrumentationTestRun(
     if any(r.GetType() not in (base_test_result.ResultType.PASS,
                                base_test_result.ResultType.SKIP)
            for r in results):
-      if self._test_instance.screenshot_dir:
-        file_name = '%s-%s.png' % (
-            test_display_name,
-            time.strftime('%Y%m%dT%H%M%S', time.localtime()))
-        screenshot_file = device.TakeScreenshot(
-            os.path.join(self._test_instance.screenshot_dir, file_name))
-        logging.info(
-            'Saved screenshot for %s to %s.',
-            test_display_name, screenshot_file)
-        if self._test_instance.should_save_images:
-          link = google_storage_helper.upload(
-              google_storage_helper.unique_name('screenshot', device=device),
-              screenshot_file,
-              bucket='chromium-render-tests')
-          for result in results:
-            result.SetLink('failure_screenshot', link)
+
+      with contextlib_ext.Optional(
+          tempfile_ext.NamedTemporaryDirectory(),
+          self._test_instance.screenshot_dir is None
+          and self._test_instance.should_save_images) as screenshot_dir:
+
+        screenshot_dir = self._test_instance.screenshot_dir or screenshot_dir
+        if screenshot_dir:
+          file_name = '%s-%s.png' % (
+              test_display_name,
+              time.strftime('%Y%m%dT%H%M%S', time.localtime()))
+          screenshot_file = device.TakeScreenshot(
+              os.path.join(self._test_instance.screenshot_dir, file_name))
+          logging.info(
+              'Saved screenshot for %s to %s.',
+              test_display_name, screenshot_file)
+          if self._test_instance.should_save_images:
+            link = google_storage_helper.upload(
+                google_storage_helper.unique_name('screenshot', device=device),
+                screenshot_file,
+                bucket='chromium-render-tests')
+            for result in results:
+              result.SetLink('failure_screenshot', link)
 
       logging.info('detected failure in %s. raw output:', test_display_name)
       for l in output: