PageLoadMetrics renderer and browser implementation.

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/logging.h"
+#include "base/metrics/histogram.h"
+#include "components/page_load_metrics/common/page_load_metrics_messages.h"
+#include "components/page_load_metrics/common/page_load_timing.h"
+#include "content/public/browser/navigation_details.h"
+#include "content/public/browser/navigation_handle.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::WebContentsObserver);
+
+namespace page_load_metrics {
+
+namespace {
+
+// True if the timing structs have the same navigation start.
+bool PageLoadTimingIsChild(const PageLoadTiming& timing,
+                           const PageLoadTiming& parent) {
+  return (parent.navigation_start.is_null() ||
+          timing.navigation_start == parent.navigation_start);
+}
+
+bool PageLoadTimingIsComplete(const PageLoadTiming& timing) {
+  return !timing.navigation_start.is_null() &&
+      !timing.response_start.is_zero() &&
+      !timing.dom_content_loaded_event_start.is_zero() &&
+         !timing.load_event_start.is_zero() &&
+         !timing.first_layout.is_zero();
+}
+
+bool PageLoadTimingIsEmpty(const PageLoadTiming& timing) {

[Bryan McQuade, 2015/09/04 12:29:26]

this one method actually seems reasonable to keep on the struct, as an
is_empty() method. sorry - i should have noted that in the last change.

The other methods do feel like they have a bit more policy specific to our use
of them in WCo, and belong here.

[Charlie Harrison, 2015/09/04 15:19:40]

Done.

+  return timing.navigation_start.is_null() &&
+      timing.response_start.is_zero() &&
+         timing.dom_content_loaded_event_start.is_zero() &&
+         timing.load_event_start.is_zero() &&
+         timing.first_layout.is_zero();
+}
+
+// Checks guaranteed ordering for performance events.
+// Assumes IsComplete().
+// Order: navigation_start => response_start =>
+// dom_content_loaded_event_start => load_event_start
+bool PageLoadTimingIsOrdered(const PageLoadTiming& timing) {
+  return !timing.response_start.is_zero() &&
+         timing.response_start < timing.dom_content_loaded_event_start &&
+         timing.dom_content_loaded_event_start < timing.load_event_start;
+}
+
+}  // namespace
+WebContentsObserver::WebContentsObserver(content::WebContents* web_contents)
+    : content::WebContentsObserver(web_contents) {}
+
+WebContentsObserver::~WebContentsObserver() {
+  RecordTimingHistograms();
+}
+
+bool WebContentsObserver::OnMessageReceived(
+    const IPC::Message& message,
+    content::RenderFrameHost* render_frame_host) {
+  bool handled = true;
+  IPC_BEGIN_MESSAGE_MAP(WebContentsObserver, message)
+    IPC_MESSAGE_HANDLER(PageLoadMetricsMsg_TimingUpdated, OnTimingUpdated)
+    IPC_MESSAGE_UNHANDLED(handled = false)
+  IPC_END_MESSAGE_MAP()
+  return handled;
+}
+
+void WebContentsObserver::DidCommitNavigation(
+    content::NavigationHandle* navigation_handle) {
+  if (IsRelevantNavigation(navigation_handle)) {
+    RecordTimingHistograms();

[Bryan McQuade, 2015/09/04 12:29:26]

I think we probably want to commit the histograms for the previous page even if
the page being navigated to is not a relevant navigation. for example imagine
you navigate from http://www.google.com/ to the new tab page (not sure if it's
possible, but let's say we did). in that case, IsRelevantNavigation() would
return false, but we still want to RecordTimingHistograms for the page being
navigated away from.

[Charlie Harrison, 2015/09/04 15:19:40]

yes! This is a mistake.

+    current_timing_ = PageLoadTiming();
+    current_navigation_ = navigation_handle;
+  }
+}
+
+void WebContentsObserver::DidFinishNavigation(
+    content::NavigationHandle* navigation_handle) {
+  if (IsRelevantNavigation(navigation_handle)) {
+    // TODO(csharrison) track aborts and log those histograms here
+    DCHECK(navigation_handle == current_navigation_);
+    current_navigation_ = nullptr;
+  }
+}
+
+void WebContentsObserver::RenderProcessGone(base::TerminationStatus status) {
+  RecordTimingHistograms();

[Bryan McQuade, 2015/09/04 12:29:26]

you may also want to do current_timing_ = PageLoadTiming(); after this, or do it
at the end of the RecordTimingHistograms impl so all calls get a 'reset' of the
timing as part of recording them.

[Charlie Harrison, 2015/09/04 15:19:40]

Done.

+}
+
+#define PAGE_LOAD_HISTOGRAM(name, sample)                           \
+  UMA_HISTOGRAM_CUSTOM_TIMES(name, sample,                          \
+                             base::TimeDelta::FromMilliseconds(10), \
+                             base::TimeDelta::FromMinutes(10), 100);
+
+void WebContentsObserver::OnTimingUpdated(const PageLoadTiming& timing) {
+  // See above comment about browser/renderer url disagreement (newtab).
+  if (!GetLastCommittedURL().SchemeIsHTTPOrHTTPS())
+    return;
+
+  if (PageLoadTimingIsChild(timing, current_timing_))
+    current_timing_ = timing;
+}
+
+void WebContentsObserver::RecordTimingHistograms() {
+  if (PageLoadTimingIsEmpty(current_timing_))
+    return;
+  else if (PageLoadTimingIsComplete(current_timing_))
+    DCHECK(PageLoadTimingIsOrdered(current_timing_));
+
+  if (!current_timing_.dom_content_loaded_event_start.is_zero()) {
+    PAGE_LOAD_HISTOGRAM("PageLoad.Timing.DOMContentLoadedEventFired",
+                        current_timing_.dom_content_loaded_event_start);
+  }
+
+  if (!current_timing_.load_event_start.is_zero()) {
+    PAGE_LOAD_HISTOGRAM("PageLoad.Timing.LoadEventFired",
+                        current_timing_.load_event_start);
+  }
+
+  if (!current_timing_.first_layout.is_zero()) {
+    PAGE_LOAD_HISTOGRAM("PageLoad.Timing.FirstLayout",
+                        current_timing_.first_layout);
+  }
+}
+
+bool WebContentsObserver::IsRelevantNavigation(
+    content::NavigationHandle* navigation_handle) {
+  // The url we see from the renderer side is not always the same as what
+  // we see from the browser side (e.g. chrome://newtab). We wan't to be
+  // sure here that we aren't logging UMA for internal pages
+  const GURL& browser_url = GetLastCommittedURL();
+  return navigation_handle->IsInMainFrame() &&
+      navigation_handle->HasCommittedDocument() &&
+      navigation_handle->GetURL().SchemeIsHTTPOrHTTPS() &&
+      browser_url.SchemeIsHTTPOrHTTPS();
+}
+
+const GURL& WebContentsObserver::GetLastCommittedURL() {
+  return web_contents()->GetLastCommittedURL();
+}
+
+}  // namespace page_load_metrics