Port perf.py's _LoginToGoogleAccount to chrome_remote_control

tools/chrome_remote_control/chrome_remote_control/browser_credentials.py

+# Copyright (c) 2012 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 chrome_remote_control import google_credentials_backend
+import logging
+import json
+
+class BrowserCredentials(object):
+  def __init__(self):
+    self._config = None
+    self._config_file = None
+
+    self._credentials_backends = \
+        [google_credentials_backend.GoogleCredentialsBackend(self)]
+
+  def _GetCredentialsBackend(self, credentials_type):
+    for backend in self._credentials_backends:
+      if credentials_type == backend.label:
+        return backend
+
+  def LoginNeeded(self, credentials_type, tab):
+    backend = self._GetCredentialsBackend(credentials_type)
+    if backend:
+      backend.LoginNeeded(tab)
+    else:
+      logging.warning('Credentials not implemented: "%s"', credentials_type)
+
+  def LoginNoLongerNeeded(self, credentials_type, tab):
+    backend = self._GetCredentialsBackend(credentials_type)
+    if backend:
+      backend.LoginNoLongerNeeded(tab)
+    else:
+      logging.warning('Credentials not implemented: "%s"', credentials_type)
+
+  def _ReadConfigFile(self):
+    try:
+      with open(self._config_file, 'r') as f:
+        contents = f.read()
+        return json.loads(contents)
+    except SyntaxError, e:
+      logging.info('Could not read %s: %s', self._config_file,
+                   str(e))
+
+  def GetConfig(self, config):
+    if self._config is None:
+      self._config = self._ReadConfigFile()
+
+    for key in self._config:
+      if self._config.get(key) is not None and key in config:
+        config[key] = self._config.get(key)
+
+    return config
+
+  def GetCredentialsConfigFile(self):
+    return self._config_file
+
+  def SetCredentialsConfigFile(self, credentials_path):
+    self._config_file = credentials_path