Added daily UMA for non-data-reduction-proxy data usage when the proxy is enabled.

BUG=325325

Review URL: https://codereview.chromium.org/106113002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@239897 0039d316-1c4b-4281-b951-d872f2087c98
   void Add(int original_content_length, int received_content_length) {
    original_.Add(original_content_length);
    received_.Add(received_content_length);
   }

   void Add(int original_content_length, int received_content_length) {
    AddInt64ToListPref(
        kNumDaysInHistory - 1, original_content_length, original_update_.Get());
    AddInt64ToListPref(
        kNumDaysInHistory - 1, received_content_length, received_update_.Get());
   }
