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 "components/page_load_metrics/common/page_load_timing.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() {}

[nasko, 2015/08/26 17:27:24]

nit: Be consistent with the constructor. Either {} or {\n}, but not a mix of the
two.

+
+bool PageLoadMetricsWebContentsObserver::OnMessageReceived(
+    const IPC::Message& message, content::RenderFrameHost* render_frame_host) {

[nasko, 2015/08/26 17:27:24]

Each parameter must be on a new line.

+  // TODO verify that this is getting called on the thread that other
+  // WebContentsObserver callbacks get invoked on (browser UI thread?).

[nasko, 2015/08/26 17:27:24]

WebContentsObserver methods are only called on the UI thread. This is guaranteed
by WebContents itself being an UI thread only object.

+  bool handled = true;
+  IPC_BEGIN_MESSAGE_MAP(PageLoadMetricsWebContentsObserver, message)
+    IPC_MESSAGE_HANDLER(PageLoadMetricsMsg_OnTimingUpdated,
+                        OnTimingUpdated)
+    IPC_MESSAGE_UNHANDLED(handled = false)
+  IPC_END_MESSAGE_MAP()
+  return handled;
+}
+
+#if 0
+
+// TODO figure out which of these hooks may actually be useful to implement.
+
+void PageLoadMetricsWebContentsObserver::DidCommitNavigation(
+    content::NavigationHandle* navigation_handle) {
+  if (!navigation_handle->IsInMainFrame())
+    return;
+
+  if (!navigation_handle->HasCommittedDocument())
+    return;
+
+  const GURL& url = navigation_handle->GetURL();
+  if (!url.SchemeIsHTTPOrHTTPS())
+    return;
+
+  page_timing_metrics_receiver_.reset(new PageTimingMetricsReceiver());
+}
+
+void PageLoadMetricsWebContentsObserver::DidNavigateMainFrame(
+      const LoadCommittedDetails& details,
+      const FrameNavigateParams& params) {
+  DCHECK(details.is_main_frame);
+
+  // TODO how are the 2 checks below different?
+  if (details.type != NAVIGATION_TYPE_NEW_PAGE)
+    return;
+  if (details.is_in_page)
+    return;
+
+}
+#endif
+
+#define PAGE_LOAD_HISTOGRAM(name, sample)                           \
+  UMA_HISTOGRAM_CUSTOM_TIMES(name,                                  \
+                             sample,                                \
+                             base::TimeDelta::FromMilliseconds(10), \
+                             base::TimeDelta::FromMinutes(10),      \
+                             100);
+
+void PageLoadMetricsWebContentsObserver::OnTimingUpdated(
+    const PageLoadTiming& timing) {
+  // TODO ignore non-HTTP/HTTPS URLs (e.g. chrome://newtab).
+
+  // TODO store the updated timing info, and log it when the next
+  // navigation occurrs.
+}
+
+// TODO call this when a page is being navigated away from
+void PageLoadMetricsWebContentsObserver::RecordTimingHistograms(
+    const PageLoadTiming& timing) {
+  if (timing.navigation_start.is_null())
+    return;
+
+  if (!timing.dom_content_loaded_event_start.is_null())
+    PAGE_LOAD_HISTOGRAM("PageLoad.Timing.DOMContentLoadedEventFired",
+        timing.dom_content_loaded_event_start - timing.navigation_start);
+
+  if (!timing.load_event_start.is_null())
+    PAGE_LOAD_HISTOGRAM("PageLoad.Timing.LoadEventFired",
+        timing.load_event_start - timing.navigation_start);
+
+  if (!timing.load_event_start.is_null())
+    PAGE_LOAD_HISTOGRAM("PageLoad.Timing.FirstLayout",
+        timing.first_layout - timing.navigation_start);
+}
+
+}  // namespace page_load_metrics