Adding DRP specfic UMA for FirstContentfulPaint

chrome/browser/page_load_metrics/observers/data_reduction_proxy_metrics_observer.h

+// Copyright 2016 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef CHROME_BROWSER_PAGE_LOAD_METRICS_OBSERVERS_DATA_REDUCTION_PROXY_METRICS_OBSERVER_H_
+#define CHROME_BROWSER_PAGE_LOAD_METRICS_OBSERVERS_DATA_REDUCTION_PROXY_METRICS_OBSERVER_H_
+
+#include "base/macros.h"
+#include "components/page_load_metrics/browser/page_load_metrics_observer.h"
+
+namespace content {
+class NavigationHandle;
+}
+
+namespace page_load_metrics {
+struct PageLoadExtraInfo;
+struct PageLoadTiming;
+}
+
+namespace data_reduction_proxy {
+
+namespace internal {
+extern const char kHistogramFirstContentfulPaintDataReductionProxy[];
+extern const char kHistogramFirstContentfulPaintDataReductionProxyAutoLofiOn[];
+extern const char kHistogramFirstContentfulPaintDataReductionProxyAutoLofiOff[];
+}
+
+class DataReductionProxyMetricsObserver
+    : public page_load_metrics::PageLoadMetricsObserver {
+ public:
+  DataReductionProxyMetricsObserver();
+  ~DataReductionProxyMetricsObserver() override;
+
+  // page_load_metrics::PageLoadMetricsObserver implementation:
+  void OnCommit(content::NavigationHandle* navigation_handle) override;
+  void OnComplete(const page_load_metrics::PageLoadTiming& timing,
+                  const page_load_metrics::PageLoadExtraInfo& info) override;
+
+  void RecordTimingHistograms(const page_load_metrics::PageLoadTiming& timing,
+                              const page_load_metrics::PageLoadExtraInfo& info);

[tbansal1, 2016/03/08 22:14:43]

can this be a const method?

[RyanSturm, 2016/03/10 00:37:58]

Done.

+
+ private:
+  // True if the navigation used LoFi.
+  bool is_using_lofi_;
+
+  // True if the navigation was proxied through the data reduction proxy.
+  bool used_data_reduction_proxy_;
+  DISALLOW_COPY_AND_ASSIGN(DataReductionProxyMetricsObserver);
+};
+
+}  // namespace data_reduction_proxy
+
+#endif  // CHROME_BROWSER_PAGE_LOAD_METRICS_OBSERVERS_DATA_REDUCTION_PROXY_METRICS_OBSERVER_H_