[telemetry] Create BrowserTestCase to reuse the browser for browser_unittest.

tools/telemetry/telemetry/page/actions/navigate_unittest.py

Index: tools/telemetry/telemetry/page/actions/navigate_unittest.py
diff --git a/tools/telemetry/telemetry/page/actions/navigate_unittest.py b/tools/telemetry/telemetry/page/actions/navigate_unittest.py
index 3e22c50f4f22aadeb643af888c5b24fd1efd6800..5d865e5648871243f89fe2d4fe64d8aad03f0cab 100644
--- a/tools/telemetry/telemetry/page/actions/navigate_unittest.py
+++ b/tools/telemetry/telemetry/page/actions/navigate_unittest.py
@@ -2,22 +2,13 @@
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
-from telemetry.page import page as page_module
 from telemetry.page.actions import navigate
 from telemetry.unittest import tab_test_case
 
 
 class NavigateActionTest(tab_test_case.TabTestCase):
-  def CreatePageFromUnittestDataDir(self, filename):
-    self.Navigate(filename)
-    return page_module.Page(
-        self._browser.http_server.UrlOf(self.test_file_path),
-        None  # In this test, we don't need a page set.
-    )
-
   def testNavigateAction(self):
-    page = self.CreatePageFromUnittestDataDir('blank.html')
-    i = navigate.NavigateAction(url=page.url)
+    i = navigate.NavigateAction(url=self.UrlOfUnittestFile('blank.html'))
     i.RunAction(self._tab)
     self.assertEquals(
         self._tab.EvaluateJavaScript('document.location.pathname;'),