Add failure screenshots and render test images to results detail.

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 93e3a63380d72855f60dfc0246adb3c5c774e230..ef260f7a51a1c174921a8434f6dae2ad0058ab37 100644
--- a/build/android/pylib/instrumentation/instrumentation_test_instance.py
+++ b/build/android/pylib/instrumentation/instrumentation_test_instance.py
@@ -498,6 +498,7 @@ class InstrumentationTestInstance(test_instance.TestInstance):
     self._store_tombstones = False
     self._initializeTombstonesAttributes(args)
 
+    self._should_save_images = None
     self._should_save_logcat = None
     self._initializeLogAttributes(args)
 
@@ -678,6 +679,7 @@ class InstrumentationTestInstance(test_instance.TestInstance):
 
   def _initializeLogAttributes(self, args):
     self._should_save_logcat = bool(args.json_results_file)
+    self._should_save_images = bool(args.json_results_file)
 
   def _initializeEditPrefsAttributes(self, args):
     if not hasattr(args, 'shared_prefs_file'):
@@ -738,6 +740,10 @@ class InstrumentationTestInstance(test_instance.TestInstance):
     return self._flags
 
   @property
+  def should_save_images(self):
+    return self._should_save_images
+
+  @property
   def should_save_logcat(self):
     return self._should_save_logcat