Adding DRP specfic UMA for FirstContentfulPaint

chrome/browser/page_load_metrics/observers/data_reduction_proxy_metrics_observer.cc

Index: chrome/browser/page_load_metrics/observers/data_reduction_proxy_metrics_observer.cc
diff --git a/chrome/browser/page_load_metrics/observers/data_reduction_proxy_metrics_observer.cc b/chrome/browser/page_load_metrics/observers/data_reduction_proxy_metrics_observer.cc
new file mode 100644
index 0000000000000000000000000000000000000000..ea77a88457d4361941904b8e813ccf1adc159fa1
--- /dev/null
+++ b/chrome/browser/page_load_metrics/observers/data_reduction_proxy_metrics_observer.cc
@@ -0,0 +1,69 @@
+// 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.
+
+#include "chrome/browser/page_load_metrics/observers/data_reduction_proxy_metrics_observer.h"
+
+#include "base/metrics/histogram.h"
+#include "components/data_reduction_proxy/core/common/data_reduction_proxy_params.h"
+#include "components/page_load_metrics/browser/page_load_metrics_observer.h"
+#include "components/page_load_metrics/browser/page_load_metrics_util.h"
+#include "components/page_load_metrics/common/page_load_timing.h"
+#include "content/public/browser/navigation_handle.h"
+
+namespace data_reduction_proxy {
+
+namespace internal {
+const char kHistogramFirstContentfulPaintDataReductionProxy[] =
+    "PageLoad.Timing2.NavigationToFirstContentfulPaint_DataReductionProxy";
+const char kHistogramFirstContentfulPaintDataReductionProxyAutoLofiOn[] =
+    "PageLoad.Timing2.NavigationToFirstContentfulPaint_DataReductionProxy_"
+    "AutoLoFiOn";
+const char kHistogramFirstContentfulPaintDataReductionProxyAutoLofiOff[] =
+    "PageLoad.Timing2.NavigationToFirstContentfulPaint_DataReductionProxy_"
+    "AutoLofiOff";
+}
+
+DataReductionProxyMetricsObserver::DataReductionProxyMetricsObserver()
+    : is_using_lofi_(false), used_data_reduction_proxy_(false) {}
+
+DataReductionProxyMetricsObserver::~DataReductionProxyMetricsObserver() {}
+
+void DataReductionProxyMetricsObserver::OnCommit(
+    content::NavigationHandle* navigation_handle) {
+  used_data_reduction_proxy_ = navigation_handle->UsedDataReductionProxy();
+  is_using_lofi_ = navigation_handle->IsUsingLofi();
+}
+void DataReductionProxyMetricsObserver::OnComplete(
+    const page_load_metrics::PageLoadTiming& timing,
+    const page_load_metrics::PageLoadExtraInfo& info) {
+  RecordTimingHistograms(timing, info);
+}
+
+void DataReductionProxyMetricsObserver::RecordTimingHistograms(
+    const page_load_metrics::PageLoadTiming& timing,
+    const page_load_metrics::PageLoadExtraInfo& info) {
+  if (!timing.first_contentful_paint.is_zero()) {

[tbansal1, 2016/03/07 18:05:04]

For readability:
if (timing.first_contentful_paint.is_zero() || !used_data_reduction_proxy_) {
return;
}

[RyanSturm, 2016/03/08 19:47:42]

Done.

+    if (used_data_reduction_proxy_) {
+      PAGE_LOAD_HISTOGRAM(
+          internal::kHistogramFirstContentfulPaintDataReductionProxy,
+          timing.first_contentful_paint);
+      if (is_using_lofi_) {
+        if (data_reduction_proxy::params::IsIncludedInLoFiEnabledFieldTrial()) {
+          PAGE_LOAD_HISTOGRAM(
+              internal::
+                  kHistogramFirstContentfulPaintDataReductionProxyAutoLofiOn,
+              timing.first_contentful_paint);
+        } else if (data_reduction_proxy::params::
+                       IsIncludedInLoFiControlFieldTrial()) {
+          PAGE_LOAD_HISTOGRAM(
+              internal::
+                  kHistogramFirstContentfulPaintDataReductionProxyAutoLofiOff,
+              timing.first_contentful_paint);
+        }
+      }
+    }
+  }
+}
+
+}  // namespace data_reduction_proxy