PageLoadMetrics renderer and browser implementation.

components/page_load_metrics/browser/page_load_metrics_web_contents_observer.h

+// 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.
+
+#ifndef COMPONENTS_PAGE_LOAD_METRICS_BROWSER_PAGE_LOAD_METRICS_WEB_CONTENTS_OBSERVER_H_
+#define COMPONENTS_PAGE_LOAD_METRICS_BROWSER_PAGE_LOAD_METRICS_WEB_CONTENTS_OBSERVER_H_
+
+#include "base/macros.h"
+#include "base/time/time.h"
+#include "components/page_load_metrics/common/page_load_timing.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"
+
+namespace content {
+class NavigationHandle;
+class RenderFrameHost;
+}  // namespace content
+
+namespace IPC {
+class Message;
+}  // namespace IPC
+
+namespace page_load_metrics {
+
+struct PageLoadTiming;
+
+// WebContentsObserver logs page load UMA metrics based on
+// IPC messages received from a MainRenderFrameObserver.
+class WebContentsObserver
+    : public content::WebContentsObserver,
+      public content::WebContentsUserData<WebContentsObserver> {
+ public:
+  ~WebContentsObserver() override;
+
+  // WebContentsObserver implementation
+  bool OnMessageReceived(const IPC::Message& message,
+                         content::RenderFrameHost* render_frame_host) override;
+  void DidCommitNavigation(
+      content::NavigationHandle* navigation_handle) override;
+  void RenderProcessGone(base::TerminationStatus status) override;
+
+ protected:
+  bool HandleMessageReceived(
+      const IPC::Message& message,
+      content::RenderFrameHost* render_frame_host);
+
+ private:
+  explicit WebContentsObserver(content::WebContents* web_contents);
+  friend class content::WebContentsUserData<WebContentsObserver>;
+  friend class WebContentsObserverTest;
+  friend class MockWebContentsObserver;

[Bryan McQuade, 2015/09/04 20:53:18]

does this need to be a friend? looking at the impl, it seems like it shouldn't
be needed.

[Charlie Harrison, 2015/09/08 23:05:15]

Either it's a friend or the explicit constructor must be made protected.

+
+  void OnTimingUpdated(content::RenderFrameHost*, const PageLoadTiming& timing);
+  void RecordTimingHistograms();
+
+  bool IsRelevantNavigation(content::NavigationHandle* navigation_handle);
+  // Used for testing, so we don't have to mock a whole WebContents
+  virtual const GURL& GetLastCommittedURL();
+
+  bool has_committed_navigation_;

[Bryan McQuade, 2015/09/04 20:53:17]

looks like this bool is no longer used. remove?

[Charlie Harrison, 2015/09/08 23:05:15]

Done.

+  content::RenderFrameHost* current_host_;

[Bryan McQuade, 2015/09/04 20:53:17]

suggest removing in favor of IsCurrentMainFrame method - see comments in cc file

+  content::NavigationHandle* current_navigation_;

[Bryan McQuade, 2015/09/04 20:53:17]

looks like this is also no longer used. remove?

[clamy, 2015/09/08 13:25:58]

In particular, the NavigationHandle will likely be deleted before this
WebContentsObserver. If you want to keep track of the NavigationHandle (but I
don't see why you should), you should implement the DidStopNavigation call,
where you will reset current_navigation_;

[Charlie Harrison, 2015/09/08 23:05:15]

Done.

+  scoped_ptr<PageLoadTiming> current_timing_;

[Bryan McQuade, 2015/09/04 20:53:17]

let's add a short comment to explain when this will be null vs non-null.

[Charlie Harrison, 2015/09/08 23:05:15]

Done.

+
+  DISALLOW_COPY_AND_ASSIGN(WebContentsObserver);
+};
+
+}  // namespace page_load_metrics
+
+#endif  // COMPONENTS_PAGE_LOAD_METRICS_BROWSER_PAGE_LOAD_METRICS_WEB_CONTENTS_OBSERVER_H_