[Telemetry] Add capability for values to reference external files.

tools/telemetry/telemetry/results/page_test_results.py

Index: tools/telemetry/telemetry/results/page_test_results.py
diff --git a/tools/telemetry/telemetry/results/page_test_results.py b/tools/telemetry/telemetry/results/page_test_results.py
index 676e003414de3f2f5ddecf2d26540316287d4189..4353563885701d64d736fa933dfc5889fa343a49 100644
--- a/tools/telemetry/telemetry/results/page_test_results.py
+++ b/tools/telemetry/telemetry/results/page_test_results.py
@@ -4,6 +4,8 @@
 
 import collections
 import copy
+import itertools
+import os
 import traceback
 
 from telemetry import value as value_module
@@ -66,6 +68,12 @@ class PageTestResults(object):
     return self._all_summary_values
 
   @property
+  def all_values(self):
+    return itertools.chain(
+        self.all_page_specific_values,
+        self.all_summary_values)
+
+  @property
   def current_page(self):
     assert self._current_page_run, 'Not currently running test.'
     return self._current_page_run.page
@@ -96,6 +104,21 @@ class PageTestResults(object):
     return failed_pages
 
   @property
+  def all_paths(self):
+    """Returns the set of all paths to referenced files.
+
+    Since we are dealing with paths, and paths are not necessarily unique even
+    if they refer to the same file, we canonicalize paths using
+    os.path.normcase and os.path.realpath before adding them to the set that we
+    return.
+    """
+    paths = set()
+    for v in self.all_values:
+      paths.update(os.path.normcase(os.path.realpath(path)) for path in v.paths)
+
+    return paths
+
+  @property
   def failures(self):
     values = self.all_page_specific_values
     return [v for v in values if isinstance(v, failure.FailureValue)]