[telemetry] Define benchmark page sets in relation to base directory.

tools/telemetry/telemetry/test.py

Index: tools/telemetry/telemetry/test.py
diff --git a/tools/telemetry/telemetry/test.py b/tools/telemetry/telemetry/test.py
index 9e064868a34a5872529c22b16ad38b609bccc4e8..aea190c84b54fcf8888b50ce5b80487375a0e4af 100644
--- a/tools/telemetry/telemetry/test.py
+++ b/tools/telemetry/telemetry/test.py
@@ -1,12 +1,23 @@
 # Copyright (c) 2013 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
+import os
+import sys
+
 from telemetry.page import page_runner
 from telemetry.page import page_set
 from telemetry.page import test_expectations
 from telemetry.page import page_test
 
 
+def GetBaseDir():
+  main_module = sys.modules['__main__']
+  if hasattr(main_module, '__file__'):
+    return os.path.dirname(main_module.__file__)
+  else:
+    return os.getcwd()
+
+
 class Test(object):
   """Base class for a Telemetry test or benchmark.
 
@@ -38,7 +49,7 @@ class Test(object):
     page_set attribute. Override to generate a custom page set.
     """
     assert hasattr(self, 'page_set'), 'This test has no "page_set" attribute.'
-    return page_set.PageSet.FromFile(self.page_set)
+    return page_set.PageSet.FromFile(os.path.join(GetBaseDir(), self.page_set))
 
   def CreateExpectations(self, ps):  # pylint: disable=W0613
     """Get the expectations this test will run with.