sandwich: Fixes two sources of KeyError task failures

tools/android/loading/sandwich_utils.py

Index: tools/android/loading/sandwich_utils.py
diff --git a/tools/android/loading/sandwich_utils.py b/tools/android/loading/sandwich_utils.py
index bbc2d9d198c7b98e6bb20fc80c8c7fa3bb9ab20a..b26077d59ff5c7c54bf0729de2368f7dcc3ce574 100644
--- a/tools/android/loading/sandwich_utils.py
+++ b/tools/android/loading/sandwich_utils.py
@@ -2,12 +2,26 @@
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
+import re
+import urlparse
+
 import common_util
 import emulation
 import sandwich_runner
 import task_manager
 
 
+class SandwichKnownError(Exception):

[pasko, 2016/07/06 12:45:52]

We are not catching this anywhere, so what is the point of having another class?

If one sees 'raise Exception(...)', the idea is clear, however, when there is
'raise SandwichKnownError(...)' it causes question like: "Is this exception
handled in a special way somewhere?", "When should this be used to replace the
regular exception?", etc.

If the only purpose is to say 'Known Error' somewhere, you can do it in the
message.

[gabadie, 2016/07/06 13:31:14]

Done.

+  pass
+
+
+def NormalizeUrl(url):
+  """Returns normalized URL such as removing trailing slashes."""
+  parsed_url = list(urlparse.urlparse(url))
+  parsed_url[2] = re.sub(r'/{2,}', r'/', parsed_url[2])
+  return urlparse.urlunparse(parsed_url)
+
+
 def NetworkSimulationTransformer(network_condition):
   """Creates a function that accepts a SandwichRunner as a parameter and sets
   network emulation options on it.