Adding in-browser correctness testing via selenium.

tools/testing/test_case.py

Index: tools/testing/test_case.py
===================================================================
--- tools/testing/test_case.py	(revision 1427)
+++ tools/testing/test_case.py	(working copy)
@@ -93,7 +93,7 @@
 
 
 class BrowserTestCase(StandardTestCase):
-  """A test case that executes inside a browser (or DumpRenderTree)."""
+  """A test case that executes inside DumpRenderTree."""
 
   def __init__(self, context, path, filename,
                fatal_static_type_errors, mode, arch, component, vm_options=None):
@@ -117,7 +117,7 @@
       # If errors were found, fail fast and show compile errors:
       if test_output.output.exit_code != 0:
         return test_output
-
+ 
     command = self.run_arch.GetRunCommand()
     test_output = self.RunCommand(command)
     # The return value of DumpRenderedTree does not indicate test failing, but