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

tools/telemetry/telemetry/core/backends/webdriver/webdriver_browser_backend.py

+# 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.
+
+from telemetry.core.backends import browser_backend
+from telemetry.core.backends.webdriver import webdriver_tab_list_backend
+
+class WebDriverBrowserBackend(browser_backend.BrowserBackend):
+  """The webdriver-based backend for controlling a locally-executed browser
+  instance, on Linux, Mac, and Windows.
+  """
+
+  def __init__(self, driver_creator, supports_extensions, options):
+    super(WebDriverBrowserBackend, self).__init__(
+        is_content_shell=False,
+        supports_extensions=supports_extensions,
+        options=options,
+        tab_list_backend=webdriver_tab_list_backend.WebDriverTabListBackend)
+
+    self._driver_creator = driver_creator
+    self._driver = None
+    self.webpagereplay_local_http_port = 80
+    self.webpagereplay_local_https_port = 443
+    self.webpagereplay_remote_http_port = self.webpagereplay_local_http_port
+    self.webpagereplay_remote_https_port = self.webpagereplay_local_https_port
+
+  def Start(self):
+    assert not self._driver
+    self._driver = self._driver_creator()
+
+  @property
+  def driver(self):
+    assert self._driver
+    return self._driver
+
+  @property
+  def supports_tab_control(self):
+    # Based on webdriver protocol API, only closing a tab is supported while
+    # activating or creating a tab is not. Thus, tab control is not supported.
+    return False
+
+  @property
+  def supports_tracing(self):
+    # Tracing is not available in IE/Firefox yet and not supported through
+    # webdriver API.
+    return False
+
+  def GetProcessName(self, _):
+    # Leave implementation details to subclass as process name depends on the
+    # type of browser.
+    raise NotImplementedError()
+
+  def Close(self):
+    self._driver.quit()
+    self._driver = None
+
+  def CreateForwarder(self, *port_pairs):
+    return browser_backend.DoNothingForwarder(*port_pairs)
+
+  def IsBrowserRunning(self):
+    # Assume the browser is running if not explicitly closed.
+    return self._driver is not None
+
+  def GetStandardOutput(self):
+    # TODO(chrisgao): check if python client can get stdout of browsers.
+    return ''
+
+  def __del__(self):
+    self.Close()