Adds UMA to measure when the data reduction proxy via header is missing

components/data_reduction_proxy/browser/data_reduction_proxy_usage_stats.h

Index: components/data_reduction_proxy/browser/data_reduction_proxy_usage_stats.h
diff --git a/components/data_reduction_proxy/browser/data_reduction_proxy_usage_stats.h b/components/data_reduction_proxy/browser/data_reduction_proxy_usage_stats.h
index 33fd29e560fa2f533fa044f1c3be60a83537c599..b78837d64277edafa21e95a7aa134b6388ca59a2 100644
--- a/components/data_reduction_proxy/browser/data_reduction_proxy_usage_stats.h
+++ b/components/data_reduction_proxy/browser/data_reduction_proxy_usage_stats.h
@@ -16,7 +16,9 @@
 #include "net/url_request/url_request.h"
 
 namespace net {
+class ProxyConfig;
 class ProxyServer;
+class HttpResponseHeaders;

[bengr, 2014/09/22 19:36:16]

Alphabetize forward declarations.

[sclittle, 2014/09/22 20:54:25]

Done.

 }
 
 namespace data_reduction_proxy {
@@ -33,6 +35,12 @@ class DataReductionProxyUsageStats
       const net::ProxyServer& proxy_server,
       DataReductionProxyBypassType bypass_type);
 
+  // For the given response |headers| that are expected to include the data
+  // reduction proxy via header, records response code UMA if the data reduction
+  // proxy via header is not present.
+  static void DetectAndRecordMissingViaHeaderResponseCode(
+      bool is_primary, const net::HttpResponseHeaders* headers);
+
   // MessageLoopProxy instance is owned by io_thread. |params| outlives
   // this class instance.
   DataReductionProxyUsageStats(DataReductionProxyParams* params,
@@ -55,10 +63,19 @@ class DataReductionProxyUsageStats
   // cause the current bypass.
   void SetBypassType(DataReductionProxyBypassType type);
 
+  // Records all the data reduction proxy bytes-related histograms for the
+  // completed URLRequest |request|.
+  void RecordBytesHistograms(
+      net::URLRequest& request,

[bengr, 2014/09/22 19:36:16]

Don't use non-const refs.

[sclittle, 2014/09/22 20:54:25]

Done. I'll change RecordBypassedBytesHistograms as well.

+      const BooleanPrefMember& data_reduction_proxy_enabled,
+      const net::ProxyConfig& data_reduction_proxy_config);
+
   // Given |data_reduction_proxy_enabled|, a |request|, and the
   // |data_reduction_proxy_config| records the number of bypassed bytes for that
   // |request| into UMAs based on bypass type. |data_reduction_proxy_enabled|
   // tells us the state of the kDataReductionProxyEnabled preference.
+  // This method is publicly visible for testing purposes; use the method
+  // RecordBytesHistograms instead of calling this method directly.

[bengr, 2014/09/22 19:36:16]

As discussed, please just friend the tests.

[sclittle, 2014/09/22 20:54:25]

Done.

   void RecordBypassedBytesHistograms(
       net::URLRequest& request,
       const BooleanPrefMember& data_reduction_proxy_enabled,
@@ -67,6 +84,13 @@ class DataReductionProxyUsageStats
   void RecordBypassEventHistograms(const net::ProxyServer& bypassed_proxy,
                                    int net_error) const;
 
+  // Records UMA of the number of response bytes of responses that are expected
+  // to have the data reduction proxy via header, but where the data reduction
+  // proxy via header is not present.
+  // This method is publicly visible for testing purposes; use the method
+  // RecordBytesHistograms instead of calling this method directly.
+  void RecordMissingViaHeaderBytes(net::URLRequest& request);

[bengr, 2014/09/22 19:36:16]

Don't use non-const refs.

[sclittle, 2014/09/22 20:54:25]

Done.

+
  private:
   enum BypassedBytesType {
     NOT_BYPASSED = 0,         /* Not bypassed. */