Retreive screenshots captured by tests from test devices.

build/android/pylib/instrumentation/instrumentation_test_instance.py

Index: build/android/pylib/instrumentation/instrumentation_test_instance.py
diff --git a/build/android/pylib/instrumentation/instrumentation_test_instance.py b/build/android/pylib/instrumentation/instrumentation_test_instance.py
index adf36d29a41c038b0a781e00495fa0658883b1e6..4f5f611f9ebfc9bd982517507155f4c9e61e34c8 100644
--- a/build/android/pylib/instrumentation/instrumentation_test_instance.py
+++ b/build/android/pylib/instrumentation/instrumentation_test_instance.py
@@ -668,6 +668,7 @@ class InstrumentationTestInstance(test_instance.TestInstance):
   def _initializeTestControlAttributes(self, args):
     self._screenshot_dir = args.screenshot_dir
     self._timeout_scale = args.timeout_scale or 1
+    self._ui_screenshot_dir = args.ui_screenshot_dir
 
   def _initializeTestCoverageAttributes(self, args):
     self._coverage_directory = args.coverage_dir
@@ -801,6 +802,10 @@ class InstrumentationTestInstance(test_instance.TestInstance):
   def total_external_shards(self):
     return self._total_external_shards
 
+  @property
+  def ui_screenshot_dir(self):
+    return self._ui_screenshot_dir
+
   #override
   def TestType(self):
     return 'instrumentation'