PageLoadMetrics renderer and browser implementation (deprecated)

components/page_load_metrics/browser/page_load_metrics_web_contents_observer.cc

+// Copyright 2015 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 "components/page_load_metrics/browser/page_load_metrics_web_contents_observer.h"
+
+#include "base/metrics/histogram.h"
+#include "components/page_load_metrics/common/page_load_metrics_messages.h"
+#include "content/public/browser/render_frame_host.h"
+#include "content/public/browser/web_contents.h"
+#include "content/public/browser/web_contents_observer.h"
+#include "content/public/browser/web_contents_user_data.h"
+#include "ipc/ipc_message.h"
+#include "ipc/ipc_message_macros.h"
+
+DEFINE_WEB_CONTENTS_USER_DATA_KEY(
+    page_load_metrics::PageLoadMetricsWebContentsObserver);
+
+namespace page_load_metrics {
+
+PageLoadMetricsWebContentsObserver::PageLoadMetricsWebContentsObserver(
+    content::WebContents* web_contents)
+    : content::WebContentsObserver(web_contents) {
+}
+
+PageLoadMetricsWebContentsObserver::~PageLoadMetricsWebContentsObserver() {}
+
+bool PageLoadMetricsWebContentsObserver::OnMessageReceived(
+    const IPC::Message& message, content::RenderFrameHost* render_frame_host) {
+  bool handled = true;
+  IPC_BEGIN_MESSAGE_MAP(PageLoadMetricsWebContentsObserver, message)
+    IPC_MESSAGE_HANDLER(PageLoadMetricsMsg_DOMContentLoadedEvent,
+                        OnDOMContentLoadedEvent)

[davidben, 2015/08/18 21:39:45]

What's the difference between this and WCO::DocumentLoadedInFrame? I guess it
includes metrics?

[Bryan McQuade, 2015/08/19 11:45:14]

Thanks for asking about this. I added some additional information about this in
the design proposal doc:
https://docs.google.com/document/d/1HJsJ5W2H_3qRdqPAUgAEo10AF8gXPTXZLUET4X4_s...

+    IPC_MESSAGE_HANDLER(PageLoadMetricsMsg_LoadEvent, OnLoadEvent)

[davidben, 2015/08/18 21:39:45]

What's the difference between this and WCO::DidFinishLoad or
WCO::DidFinishNavigation?

[Bryan McQuade, 2015/08/19 11:45:14]

Same as above.

+    IPC_MESSAGE_HANDLER(PageLoadMetricsMsg_FirstLayout, OnFirstLayout)
+    IPC_MESSAGE_UNHANDLED(handled = false)
+  IPC_END_MESSAGE_MAP()
+  return handled;
+}
+
+#define PAGE_LOAD_HISTOGRAM(name, sample)                           \
+  UMA_HISTOGRAM_CUSTOM_TIMES(name,                                  \
+                             sample,                                \
+                             base::TimeDelta::FromMilliseconds(10), \
+                             base::TimeDelta::FromMinutes(10),      \
+                             100);
+
+void PageLoadMetricsWebContentsObserver::OnDOMContentLoadedEvent(
+    base::TimeDelta dom_content_loaded_event) {
+  PAGE_LOAD_HISTOGRAM(
+      "PageLoad.TimeTo.DOMContentLoadedEvent", dom_content_loaded_event);

[Randy Smith (Not in Mondays), 2015/08/17 19:31:07]

If these are new UMAs, shouldn't they have entries in
tools/metrics/histograms/histograms.xml?

[Bryan McQuade, 2015/08/25 13:53:35]

Done.

+}
+
+void PageLoadMetricsWebContentsObserver::OnLoadEvent(
+    base::TimeDelta load_event) {
+  PAGE_LOAD_HISTOGRAM("PageLoad.TimeTo.LoadEvent", load_event);
+}
+
+void PageLoadMetricsWebContentsObserver::OnFirstLayout(
+    base::TimeDelta first_layout) {
+  PAGE_LOAD_HISTOGRAM("PageLoad.TimeTo.FirstLayout", first_layout);
+}
+
+}  // namespace page_load_metrics