Framework to ascribe all network data use to a source.

chrome/browser/data_use_measurement/chrome_data_use_ascriber_service.h

+// Copyright 2016 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 CHROME_BROWSER_DATA_USE_MEASUREMENT_CHROME_DATA_USE_ASCRIBER_SERVICE_H_
+#define CHROME_BROWSER_DATA_USE_MEASUREMENT_CHROME_DATA_USE_ASCRIBER_SERVICE_H_
+
+#include "components/keyed_service/core/keyed_service.h"
+
+namespace content {
+class NavigationHandle;
+class RenderFrameHost;
+}
+
+class IOThread;
+
+namespace data_use_measurement {
+class ChromeDataUseAscriber;
+
+// UI thread functionality of |ChromeDataUseAscriber|.
+//
+// Listens to navigation and frame events on UI thread and propagates them to

[bengr, 2016/09/01 00:16:55]

on -> on the

[Not at Google. Contact bengr, 2016/09/07 23:38:37]

Done.

+// |ChromeDataUseAscriber| on the IO thread. This class depends on external
+// WebContentsObservers to propagate events to itself because each
+// WebContents instance requires its own WebContentsObserver instance.
+//
+// Created and destroyed on the UI thread. Public methods should only be called
+// on the UI thread.
+class ChromeDataUseAscriberService : public KeyedService {
+ public:
+  ChromeDataUseAscriberService();
+  ~ChromeDataUseAscriberService() override;
+
+  // Called when a render frame a created. Propagates this information to
+  // |ascriber_| on the IO thread. |RenderFrameHost| methods cannot be called
+  // on the IO thread, so only routing IDs of |render_frame_host| and its parent
+  // are propagated.
+  void RenderFrameCreated(content::RenderFrameHost* render_frame_host);
+
+  // Called when a render frame a deleted. Propagates this information to
+  // |ascriber_| on the IO thread. |RenderFrameHost| methods cannot be called
+  // on the IO thread, so only routing IDs of |render_frame_host| and its parent
+  // are propagated.
+  void RenderFrameDeleted(content::RenderFrameHost* render_frame_host);
+
+  // Called when a navigation is started. Propagates main frame navigation
+  // start to the |ascriber_| on the IO thread. |NavigationHandle| methods
+  // cannot be called on the IO thread, so the pointer is cast to void*.
+  void DidStartNavigation(content::NavigationHandle* navigation_handle);
+
+  // Called when a navigation is finished. Propagates main frame navigation
+  // finish to the |ascriber_| on the IO thread. |NavigationHandle| methods
+  // cannot be called on the IO thread, so the pointer is cast to void*.
+  void DidFinishNavigation(content::NavigationHandle* navigation_handle);
+
+  // Called when a navigation is redirected. Propagates main frame navigation
+  // redirect to the |ascriber_| on the IO thread. |NavigationHandle| methods
+  // cannot be called on the IO thread, so the pointer is cast to void*.
+  void DidRedirectNavigation(content::NavigationHandle* navigation_handle);
+
+ private:
+  void InitOnIOThread(IOThread* io_thread);
+  void SetDataUseAscriber(ChromeDataUseAscriber* ascriber);

[bengr, 2016/09/01 00:16:55]

I don't understand the relationship. Who owns the ascriber? Why are these
methods duplicated there?

[Not at Google. Contact bengr, 2016/09/07 23:38:37]

This class listens to callbacks on the UI thread and propagates them to
ChromeDataUseAscriber on the IO thread.
Ascriber is owned in IOThread globals.

+
+  // |ascriber_| outlives this instance.
+  ChromeDataUseAscriber* ascriber_;
+};
+
+}  // namespace data_use_measurement

[bengr, 2016/09/01 00:16:55]

DISALLOW_COPY_AND_ASSIGN?

[Not at Google. Contact bengr, 2016/09/07 23:38:37]

Done.

+
+#endif  // CHROME_BROWSER_DATA_USE_MEASUREMENT_CHROME_DATA_USE_ASCRIBER_SERVICE_H_