Renamed google.protobuf to protobuf26

third_party/protobuf26/README.chromium

+This directory contains google.protobuf module version 2.6.0 build 0.
+
+sergiyb@: It has been manually renamed to protobuf26. This is needed to avoid
+conflicts with a built-in google.protobuf module found on many developer
+machines. The long-term solution to this problem, however, should be virtualenv.
+Unfortunately due to limited time and lack of experience, it was not a
+reasonable short-term solution.
+
+If you need to update this package, please make sure that you replace all
+the references to google.protobuf in the package itself with protobuf26, e.g.
+
+  from google.protobuf import text_format
+  import google.protobuf
+
+becomes
+
+  from protobuf26 import text_format
+  import protobuf26
+
+Bug tracking setting up virtualenv for depot_tools is https://crbug.com/496241.