shill: Add metric to track corrupted profiles

New metric Network.Shill.CorruptedProfile.

BUG=chromium-os:38669
TEST=1. Unit tests
     2. Stop shill
        Corrupt /var/cache/shill/default.profile by adding junk
        Start shill
        Verify new metric appears in chrome://histograms

Change-Id: I629ed00884ecd2d2fe90744583bd72bf2e9e6af4
Reviewed-on: https://gerrit.chromium.org/gerrit/43556
Reviewed-by: Thieu Le <thieule@chromium.org>
Tested-by: Thieu Le <thieule@chromium.org>
Commit-Queue: Thieu Le <thieule@chromium.org>
diff --git a/default_profile.h b/default_profile.h
index 50c82bb..c31997c 100644
--- a/default_profile.h
+++ b/default_profile.h
@@ -27,6 +27,7 @@
   static const char kDefaultId[];
 
   DefaultProfile(ControlInterface *control,
+                 Metrics *metrics,
                  Manager *manager,
                  const FilePath &storage_path,
                  const std::string &profile_id,