New Task Manager - Phase 1.1: Implement Browser Process Task Providing

chrome/browser/task_management/private/tasks_providers/task_provider.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 CHROME_BROWSER_TASK_MANAGEMENT_PRIVATE_TASKS_PROVIDERS_TASK_PROVIDER_H_
+#define CHROME_BROWSER_TASK_MANAGEMENT_PRIVATE_TASKS_PROVIDERS_TASK_PROVIDER_H_
+
+#include "chrome/browser/task_management/private/tasks_providers/task_provider_observer.h"
+
+namespace task_management {
+

[ncarter (slow), 2015/03/27 18:16:22]

Merits a class comment. The comment before the old ResourceProvider class can be
a starting point.

https://google-styleguide.googlecode.com/svn/trunk/cppguide.html#Class_Comments

In particular you should explain the contract between the provider and its
observer, and the behaviors that concrete implementations of TaskProvider must
implement. E.g.: when StartUpdating is called, the provider need to notify the
observer of preexisting tasks?

[afakhry, 2015/03/31 00:19:20]

Done.

+class TaskProvider {
+ public:
+  TaskProvider();
+  virtual ~TaskProvider();
+
+  // Should return the task associated to the specified ids of a URLRequest,
+  // or nullptr if the desired task does not belong to this provider.
+  virtual scoped_refptr<Task> GetTaskOfUrlRequest(int origin_pid,
+                                                  int child_id,
+                                                  int route_id) = 0;
+
+  void SetObserver(TaskProviderObserver* observer);
+  void ClearObserver();
+
+ protected:
+  // we keep updating as long as the |observer_| is set for this provider.
+  // StopUpdating() will be called after the |observer_| is cleared.
+  virtual void StartUpdating() = 0;
+  virtual void StopUpdating() = 0;
+
+// ----------------------------------------------------------------------
+// Fields:
+// ----------------------------------------------------------------------

[ncarter (slow), 2015/03/27 18:16:22]

Not needed.

[afakhry, 2015/03/31 00:19:20]

Done.

+  // We support only one single obsever which will be the sampler in this case.
+  TaskProviderObserver* observer_;

[ncarter (slow), 2015/03/27 18:16:22]

This should be private. The methods of the base class are the only ones that
should be able to update the observer_ value.

[afakhry, 2015/03/31 00:19:20]

Done.

+
+  DISALLOW_COPY_AND_ASSIGN(TaskProvider);
+};
+
+}  // namespace task_management
+
+#endif  // CHROME_BROWSER_TASK_MANAGEMENT_PRIVATE_TASKS_PROVIDERS_TASK_PROVIDER_H_