[telemetry] Add a webdriver backend with support for IE.

tools/telemetry/telemetry/core/chrome/browser_backend.py

Index: tools/telemetry/telemetry/core/chrome/browser_backend.py
diff --git a/tools/telemetry/telemetry/core/chrome/browser_backend.py b/tools/telemetry/telemetry/core/chrome/browser_backend.py
index c910e6d5f26882b5c214f00a83248fe330f3059e..c0c23466ab546986c4cb4aa7c972d2e9aff0858f 100644
--- a/tools/telemetry/telemetry/core/chrome/browser_backend.py
+++ b/tools/telemetry/telemetry/core/chrome/browser_backend.py
@@ -32,6 +32,7 @@ class BrowserBackend(object):
 
   def __init__(self, is_content_shell, supports_extensions, options):
     self.browser_type = options.browser_type
+    self.webdriver_based = False

[nduca, 2013/07/30 06:49:45]

why is this needed? This is like having a isCrOS on the browserbackend, which of
course we'd say no to.

[chrisgao (Use stgao instead), 2013/07/31 19:05:41]

Removed.

     self.is_content_shell = is_content_shell
     self._supports_extensions = supports_extensions
     self.options = options
@@ -250,15 +251,3 @@ class BrowserBackend(object):
 
   def GetStackTrace(self):
     raise NotImplementedError()
-
-class DoNothingForwarder(object):
-  def __init__(self, *port_pairs):
-    self._host_port = port_pairs[0].local_port
-
-  @property
-  def url(self):
-    assert self._host_port
-    return 'http://127.0.0.1:%i' % self._host_port
-
-  def Close(self):
-    self._host_port = None