Adding TabRestore PLM UMA

chrome/browser/page_load_metrics/observers/tab_restore_page_load_metrics_observer.cc

Index: chrome/browser/page_load_metrics/observers/tab_restore_page_load_metrics_observer.cc
diff --git a/chrome/browser/page_load_metrics/observers/tab_restore_page_load_metrics_observer.cc b/chrome/browser/page_load_metrics/observers/tab_restore_page_load_metrics_observer.cc
new file mode 100644
index 0000000000000000000000000000000000000000..1223f5f5c90bcb184f6eb15b04c07e4cd98657c9
--- /dev/null
+++ b/chrome/browser/page_load_metrics/observers/tab_restore_page_load_metrics_observer.cc
@@ -0,0 +1,85 @@
+// 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/tab_restore_page_load_metrics_observer.h"
+
+#include <string>
+
+#include "base/metrics/histogram_macros.h"
+#include "chrome/browser/page_load_metrics/page_load_metrics_util.h"
+#include "content/public/browser/navigation_controller.h"
+#include "content/public/browser/navigation_entry.h"
+#include "content/public/browser/navigation_handle.h"
+#include "content/public/browser/restore_type.h"
+#include "content/public/browser/web_contents.h"
+#include "ui/base/page_transition_types.h"
+
+namespace {
+
+const char kHistogramNetworkBytes[] =
+    "PageLoad.Clients.TabRestore.Experimental.Bytes.Network";
+const char kHistogramCacheBytes[] =
+    "PageLoad.Clients.TabRestore.Experimental.Bytes.Cache";
+const char kHistogramTotalBytes[] =
+    "PageLoad.Clients.TabRestore.Experimental.Bytes.Total";
+
+}  // namespace
+
+TabRestorePageLoadMetricsObserver::TabRestorePageLoadMetricsObserver()
+    : cache_bytes_(0), network_bytes_(0) {}
+
+TabRestorePageLoadMetricsObserver::~TabRestorePageLoadMetricsObserver() {}
+
+page_load_metrics::PageLoadMetricsObserver::ObservePolicy
+TabRestorePageLoadMetricsObserver::OnStart(
+    content::NavigationHandle* navigation_handle,
+    const GURL& currently_committed_url,
+    bool started_in_foreground) {
+  return IsTabRestore(navigation_handle) ? CONTINUE_OBSERVING : STOP_OBSERVING;
+}
+
+void TabRestorePageLoadMetricsObserver::OnLoadedResource(
+    const page_load_metrics::ExtraRequestInfo& extra_request_info) {
+  if (extra_request_info.was_cached) {
+    cache_bytes_ += extra_request_info.raw_body_bytes;
+  } else {
+    network_bytes_ += extra_request_info.raw_body_bytes;
+  }
+}
+
+page_load_metrics::PageLoadMetricsObserver::ObservePolicy
+TabRestorePageLoadMetricsObserver::FlushMetricsOnAppEnterBackground(
+    const page_load_metrics::PageLoadTiming& timing,
+    const page_load_metrics::PageLoadExtraInfo& info) {
+  // FlushMetricsOnAppEnterBackground is invoked on Android in cases where the
+  // app is about to be backgrounded, as part of the Activity.onPause()
+  // flow. After this method is invoked, Chrome may be killed without further
+  // notification, so we record final metrics collected up to this point.
+  if (!info.did_commit) {
+    RecordByteHistograms();
+  }
+  return STOP_OBSERVING;
+}
+
+void TabRestorePageLoadMetricsObserver::OnComplete(
+    const page_load_metrics::PageLoadTiming& timing,
+    const page_load_metrics::PageLoadExtraInfo& info) {
+  RecordByteHistograms();
+}
+
+void TabRestorePageLoadMetricsObserver::RecordByteHistograms() {
+  PAGE_BYTES_HISTOGRAM(kHistogramNetworkBytes, network_bytes_);
+  PAGE_BYTES_HISTOGRAM(kHistogramCacheBytes, cache_bytes_);
+  PAGE_BYTES_HISTOGRAM(kHistogramTotalBytes, network_bytes_ + cache_bytes_);
+}
+
+bool TabRestorePageLoadMetricsObserver::IsTabRestore(
+    content::NavigationHandle* navigation_handle) {
+  // Only count restored tabs, and eliminate forward-back navigations, as
+  // restored tab history is considered a restored navigation until they are
+  // loaded the first time.
+  return navigation_handle->GetRestoreType() != content::RestoreType::NONE &&
+         !(navigation_handle->GetPageTransition() &
+           ui::PAGE_TRANSITION_FORWARD_BACK);
+}