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..406034d1d59f1cda549664b1e26995163d376f06 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):
+  pass
+
+
+def NormalizeUrl(url):
+  """Returns normalized URL with 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.