Add FailureValue and wire it through PageTestResults.

tools/telemetry/telemetry/value/summary.py

Index: tools/telemetry/telemetry/value/summary.py
diff --git a/tools/telemetry/telemetry/value/summary.py b/tools/telemetry/telemetry/value/summary.py
index 71369fcfd037cfe80eaa47461d0f95edf44f857a..a715517ad46dbf9c3b90cf51dbdff22753607ba4 100644
--- a/tools/telemetry/telemetry/value/summary.py
+++ b/tools/telemetry/telemetry/value/summary.py
@@ -4,6 +4,7 @@
 
 from collections import defaultdict
 
+from telemetry.value import failure
 from telemetry.value import merge_values
 
 class Summary(object):
@@ -58,7 +59,9 @@ class Summary(object):
     return self._interleaved_computed_per_page_values_and_summaries
 
   def _ComputePerPageValues(self, all_page_specific_values):
-    all_successful_page_values = all_page_specific_values
+    all_successful_page_values = [
+        v for v in all_page_specific_values if not isinstance(
+            v, failure.FailureValue)]
 
     # We will later need to determine how many values were originally created
     # for each value name, to apply a workaround meant to clean up the printf