Adding functionality for full proto names

There are some device protos which have the same field names (e.g. enabled).
Currently the policy_server cannot differentiate between them. This will
all setting these by: "groupname.fieldname", e.g:
"device_power_peak_shift.enabled".

TEST=Locally deployed and tested
BUG=TBD

Change-Id: I9565f3082ed192e787b2a00efec1ae29ebe195f2
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1790534Reviewed-by: Denis Kuznetsov <antrim@chromium.org>
Reviewed-by: Roman Sorokin [CET] <rsorokin@chromium.org>
Commit-Queue: Derek Beckett <dbeckett@chromium.org>
Cr-Commit-Position: refs/heads/master@{#694856}

components/policy/test_support/policy_testserver.py

@@ -1004,7 +1004,12 @@ class PolicyRequestHandler(BaseHTTPServer.BaseHTTPRequestHandler):
       # policy config file.
       for field in group_message.DESCRIPTOR.fields:
         field_value = None
-        if field.name in policies:
+        full_name = '{}.{}'.format(group.name, field.name)
+        if full_name in policies:
+          got_fields = True
+          field_value = policies[full_name]
+          self.SetProtobufMessageField(group_message, field, field_value)
+        elif field.name in policies:
           got_fields = True
           field_value = policies[field.name]
           self.SetProtobufMessageField(group_message, field, field_value)