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..59f20449bc8eb58628c03d7d8e8b55d18b2ac122
--- /dev/null
+++ b/chrome/browser/page_load_metrics/observers/data_reduction_proxy_metrics_observer.cc
@@ -0,0 +1,80 @@
+// 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 "chrome/browser/renderer_host/chrome_navigation_data.h"
+#include "components/data_reduction_proxy/core/browser/data_reduction_proxy_data.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_data.h"
+#include "content/public/browser/navigation_handle.h"
+
+namespace data_reduction_proxy {
+
+namespace internal {
+
+const char kHistogramFirstContentfulPaintDataReductionProxy[] =
+    "PageLoad.Clients.DataReductionProxy.Timing2."
+    "NavigationToFirstContentfulPaint";
+const char kHistogramFirstContentfulPaintDataReductionProxyLoFiOn[] =
+    "PageLoad.Clients.DataReductionProxy.LoFiOn.Timing2."
+    "NavigationToFirstContentfulPaint";
+
+}  // namespace internal
+
+DataReductionProxyMetricsObserver::DataReductionProxyMetricsObserver()
+    : lofi_requested_(false), used_data_reduction_proxy_(false) {}
+
+DataReductionProxyMetricsObserver::~DataReductionProxyMetricsObserver() {}
+
+// Check if the NavigationData indicates anything about the DataReductionProxy.
+void DataReductionProxyMetricsObserver::OnCommit(
+    content::NavigationHandle* navigation_handle) {
+  // As documented in content/public/browser/navigation_handle.h, this
+  // NavigationData is a clone of the NavigationData instance returned from
+  // ResourceDispatcherHostDelegate::GetNavigationData during commit.
+  // Because ChromeResourceDispatcherHostDelegate always returns a
+  // ChromeNavigationData, it is safe to static_cast here.
+  ChromeNavigationData* chrome_navigation_data =
+      static_cast<ChromeNavigationData*>(
+          navigation_handle->GetNavigationData());
+  if (!chrome_navigation_data)
+    return;
+  data_reduction_proxy::DataReductionProxyData* data =
+      chrome_navigation_data->GetDataReductionProxyData();
+  if (!data)
+    return;
+  used_data_reduction_proxy_ = data->used_data_reduction_proxy();
+  lofi_requested_ = data->lofi_requested();
+}
+
+void DataReductionProxyMetricsObserver::OnComplete(
+    const page_load_metrics::PageLoadTiming& timing,
+    const page_load_metrics::PageLoadExtraInfo& info) {
+  RecordTimingHistograms(timing, info);
+}
+
+// Record first contentful paint UMA for various DataReductionProxy
+// configurations.
+void DataReductionProxyMetricsObserver::RecordTimingHistograms(
+    const page_load_metrics::PageLoadTiming& timing,
+    const page_load_metrics::PageLoadExtraInfo& info) const {
+  if (!used_data_reduction_proxy_ ||
+      !WasStartedInForegroundEventInForeground(timing.first_contentful_paint,
+                                               info))
+    return;
+  PAGE_LOAD_HISTOGRAM(
+      internal::kHistogramFirstContentfulPaintDataReductionProxy,
+      timing.first_contentful_paint);
+  if (!lofi_requested_)
+    return;
+  PAGE_LOAD_HISTOGRAM(
+      internal::kHistogramFirstContentfulPaintDataReductionProxyLoFiOn,
+      timing.first_contentful_paint);
+}
+
+}  // namespace data_reduction_proxy