Added the --screenshot option.

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 2d574de1fd2017149062cb63c9c4eb12e6023bad..46621115b00ac169f1ae72d4305f6a81d329cb36 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
@@ -3,6 +3,7 @@
 # found in the LICENSE file.
 
 import logging
+import os
 import re
 import time
 
@@ -263,6 +264,15 @@ 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()))
+        saved_dir = device.TakeScreenshot(
+            os.path.join(self._test_instance.screenshot_dir, file_name))
+        logging.info(
+            'Saved screenshot for %s to %s.',
+            test_display_name, saved_dir)
       logging.info('detected failure in %s. raw output:', test_display_name)
       for l in output:
         logging.info('  %s', l)