[Telemetry] Change the page's file_path param to base_dir param

tools/telemetry/telemetry/page/page_set_unittest.py

Index: tools/telemetry/telemetry/page/page_set_unittest.py
diff --git a/tools/telemetry/telemetry/page/page_set_unittest.py b/tools/telemetry/telemetry/page/page_set_unittest.py
index 9545c70881422bc5b45b668c865c7ad1ffaac4c0..5edec41d691918682bbdb77ac933dc30c585739b 100644
--- a/tools/telemetry/telemetry/page/page_set_unittest.py
+++ b/tools/telemetry/telemetry/page/page_set_unittest.py
@@ -15,7 +15,7 @@ class TestPageSet(unittest.TestCase):
   def testServingDirs(self):
     directory_path = tempfile.mkdtemp()
     try:
-      ps = page_set.PageSet(serving_dirs=['a/b'], file_path=directory_path)
+      ps = page_set.PageSet(serving_dirs=['a/b'], base_dir=directory_path)
       ps.AddUserStory(page.Page('file://c/test.html', ps, ps.base_dir))
       ps.AddUserStory(page.Page('file://c/test.js', ps, ps.base_dir))
       ps.AddUserStory(page.Page('file://d/e/../test.html', ps, ps.base_dir))
@@ -34,7 +34,7 @@ class TestPageSet(unittest.TestCase):
     directory_path = tempfile.mkdtemp()
     try:
       absolute_dir = os.path.join(directory_path, 'a', 'b')
-      ps = page_set.PageSet(file_path=directory_path,
+      ps = page_set.PageSet(base_dir=directory_path,
                             serving_dirs=['', directory_path, absolute_dir])
       real_directory_path = os.path.realpath(directory_path)
       real_absolute_dir = os.path.realpath(absolute_dir)