Converging the two previews type enums

components/data_reduction_proxy/core/browser/data_reduction_proxy_pingback_client.cc

Index: components/data_reduction_proxy/core/browser/data_reduction_proxy_pingback_client.cc
diff --git a/components/data_reduction_proxy/core/browser/data_reduction_proxy_pingback_client.cc b/components/data_reduction_proxy/core/browser/data_reduction_proxy_pingback_client.cc
index fb72e14dec8197adc3eabf3d9b5533c66ab32201..8754d8ff25fe0533332d4f1f552ec0054c12d630 100644
--- a/components/data_reduction_proxy/core/browser/data_reduction_proxy_pingback_client.cc
+++ b/components/data_reduction_proxy/core/browser/data_reduction_proxy_pingback_client.cc
@@ -111,6 +111,10 @@ void AddDataToPageloadMetrics(const DataReductionProxyData& request_data,
     request->set_previews_type(PageloadMetrics_PreviewsType_NONE);
   }
 
+  // If server Lo-Fi or a server Lite Page was not shown, report unknown opt out
+  // state even if opt out information was reported. Similarly, if the app was

[megjablon, 2017/05/11 23:49:45]

I don't understand this first sentence. 

[RyanSturm, 2017/05/15 16:23:08]

Done.

+  // backgrounded (android) do not report opt out information as an opt out can

[megjablon, 2017/05/11 23:49:45]

nit: capitalize Android

Also does it matter if we set the opt out value if the pingback was already
sent?

[RyanSturm, 2017/05/15 16:23:08]

Done.

Re-worded

+  // occur after the app is backgrounded and the pingback is sent.
   if (!was_preview_shown || timing.app_background_occurred) {
     request->set_previews_opt_out(PageloadMetrics_PreviewsOptOut_UNKNOWN);
     return;