Adding previews information to PLM UKM

chrome/browser/page_load_metrics/observers/previews_ukm_observer.cc

+// Copyright 2017 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/previews_ukm_observer.h"
+
+#include "base/optional.h"
+#include "base/time/time.h"
+#include "chrome/browser/browser_process.h"
+#include "chrome/browser/loader/chrome_navigation_data.h"
+#include "chrome/browser/page_load_metrics/page_load_metrics_observer.h"
+#include "chrome/browser/page_load_metrics/page_load_metrics_util.h"
+#include "chrome/browser/previews/previews_infobar_delegate.h"
+#include "chrome/common/page_load_metrics/page_load_timing.h"
+#include "components/data_reduction_proxy/core/browser/data_reduction_proxy_data.h"
+#include "components/ukm/ukm_source.h"
+#include "content/public/browser/navigation_handle.h"
+#include "services/metrics/public/cpp/ukm_entry_builder.h"
+#include "services/metrics/public/cpp/ukm_recorder.h"
+
+namespace previews {
+
+namespace {
+
+const char kPreviewsName[] = "Previews";
+const char kPreviewsServerLoFi[] = "server_lofi";
+const char kPreviewsClientLoFi[] = "client_lofi";
+const char kPreviewsLitePage[] = "lite_page";
+const char kPreviewsOptOut[] = "opt_out";
+
+}  // namespace
+
+PreviewsUKMObserver::PreviewsUKMObserver() {}

[tbansal1, 2017/07/12 21:58:45]

Is it useful to add sequence checker on this class? It is not obvious that
opt-out broadcast events are received on the same sequence as the other
notification events.

[RyanSturm, 2017/07/17 18:48:30]

Done.

+
+PreviewsUKMObserver::~PreviewsUKMObserver() {}
+
+page_load_metrics::PageLoadMetricsObserver::ObservePolicy
+PreviewsUKMObserver::OnCommit(content::NavigationHandle* navigation_handle,
+                              ukm::SourceId source_id) {
+  // 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 CONTINUE_OBSERVING;
+  data_reduction_proxy::DataReductionProxyData* data =
+      chrome_navigation_data->GetDataReductionProxyData();
+  if (data && data->used_data_reduction_proxy() && data->lite_page_received()) {
+    lite_page_seen_ = true;
+  }
+
+  return CONTINUE_OBSERVING;
+}
+
+page_load_metrics::PageLoadMetricsObserver::ObservePolicy
+PreviewsUKMObserver::OnStart(content::NavigationHandle* navigation_handle,
+                             const GURL& currently_committed_url,
+                             bool started_in_foreground) {
+  if (!started_in_foreground)
+    return STOP_OBSERVING;
+  return CONTINUE_OBSERVING;
+}
+
+page_load_metrics::PageLoadMetricsObserver::ObservePolicy
+PreviewsUKMObserver::FlushMetricsOnAppEnterBackground(
+    const page_load_metrics::mojom::PageLoadTiming& timing,
+    const page_load_metrics::PageLoadExtraInfo& info) {
+  RecordPreviewsTypes(info);
+  return STOP_OBSERVING;
+}
+
+void PreviewsUKMObserver::OnComplete(
+    const page_load_metrics::mojom::PageLoadTiming& timing,
+    const page_load_metrics::PageLoadExtraInfo& info) {
+  RecordPreviewsTypes(info);
+}
+
+void PreviewsUKMObserver::RecordPreviewsTypes(
+    const page_load_metrics::PageLoadExtraInfo& info) {
+  // Only record previews types when they occur.
+  if (!server_lofi_seen_ && !client_lofi_seen_ && !lite_page_seen_)
+    return;
+  ukm::UkmRecorder* ukm_recorder = g_browser_process->ukm_recorder();
+  if (!ukm_recorder)
+    return;
+  std::unique_ptr<ukm::UkmEntryBuilder> builder =
+      ukm_recorder->GetEntryBuilder(info.source_id, kPreviewsName);
+  if (server_lofi_seen_)
+    builder->AddMetric(kPreviewsServerLoFi, true);
+  if (client_lofi_seen_)
+    builder->AddMetric(kPreviewsClientLoFi, true);
+  if (lite_page_seen_)
+    builder->AddMetric(kPreviewsLitePage, true);
+  if (opt_out_occurred_)
+    builder->AddMetric(kPreviewsOptOut, true);
+}
+
+void PreviewsUKMObserver::OnLoadedResource(
+    const page_load_metrics::ExtraRequestCompleteInfo&
+        extra_request_complete_info) {
+  if (extra_request_complete_info.data_reduction_proxy_data) {
+    if (extra_request_complete_info.data_reduction_proxy_data
+            ->lofi_received()) {
+      server_lofi_seen_ = true;
+    }
+    if (extra_request_complete_info.data_reduction_proxy_data
+            ->client_lofi_requested()) {
+      client_lofi_seen_ = true;

[tbansal1, 2017/07/12 21:58:45]

Is this |seen| or |requested|?

[RyanSturm, 2017/07/17 18:48:30]

They are synonymous in that adding the range header means the image could or
could not be different regardless of what headers the server returns.

+    }
+  }
+}
+
+void PreviewsUKMObserver::OnEventOccurred(const void* const event_key) {
+  if (event_key == PreviewsInfoBarDelegate::OptOutEventKey())
+    opt_out_occurred_ = true;
+}
+
+}  // namespace previews