Adding UMA for data reduction proxy page load size/savings

chrome/browser/page_load_metrics/observers/data_reduction_proxy_metrics_observer.h

Index: chrome/browser/page_load_metrics/observers/data_reduction_proxy_metrics_observer.h
diff --git a/chrome/browser/page_load_metrics/observers/data_reduction_proxy_metrics_observer.h b/chrome/browser/page_load_metrics/observers/data_reduction_proxy_metrics_observer.h
index 7a13346dcb575a381aa68a7aefde8b4a26c6f0b8..9da37adce997b08c95054aae897583d5a346c75a 100644
--- a/chrome/browser/page_load_metrics/observers/data_reduction_proxy_metrics_observer.h
+++ b/chrome/browser/page_load_metrics/observers/data_reduction_proxy_metrics_observer.h
@@ -90,12 +90,17 @@ class DataReductionProxyMetricsObserver
                     const page_load_metrics::PageLoadExtraInfo& info) override;
   void OnParseStop(const page_load_metrics::PageLoadTiming& timing,
                    const page_load_metrics::PageLoadExtraInfo& info) override;
+  void OnLoadedResource(
+      const page_load_metrics::ExtraRequestInfo& extra_request_info) override;
 
  private:
   // Sends the page load information to the pingback client.
   void SendPingback(const page_load_metrics::PageLoadTiming& timing,
                     const page_load_metrics::PageLoadExtraInfo& info);
 
+  // Record UMA of page size when the observer is about to be deleted.
+  void RecordPageSizeUMA();

[tbansal1, 2017/01/18 22:35:20]

s/Record/Records/

[RyanSturm, 2017/01/18 22:57:49]

Done.

+
   // Gets the default DataReductionProxyPingbackClient. Overridden in testing.
   virtual DataReductionProxyPingbackClient* GetPingbackClient() const;
 
@@ -105,6 +110,22 @@ class DataReductionProxyMetricsObserver
   // The browser context this navigation is operating in.
   content::BrowserContext* browser_context_;
 
+  // The number of requests that used data reduction proxy.
+  int num_data_reduction_proxy_requests_;
+
+  // The number of request that used the network.

[tbansal1, 2017/01/18 22:35:20]

How is this determined? What happens if the cached resource is validated?

[RyanSturm, 2017/01/18 22:57:49]

Done.

+  int num_network_requests_;
+
+  // The total content network bytes that the user would have downloaded if they
+  // were not using data reduction proxy.
+  int64_t original_network_bytes_;
+
+  // The total network bytes loaded through data reduction proxy

[tbansal1, 2017/01/18 22:35:20]

missing period at end.

+  int64_t network_bytes_proxied_;
+
+  // The total network bytes used.
+  int64_t network_bytes_;
+
   DISALLOW_COPY_AND_ASSIGN(DataReductionProxyMetricsObserver);
 };