Add ModuleInspector

chrome/browser/conflicts/module_inspector_win.h

+// Copyright 2017 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_CONFLICTS_MODULE_INSPECTOR_WIN_H_
+#define CHROME_BROWSER_CONFLICTS_MODULE_INSPECTOR_WIN_H_
+
+#include <queue>
+
+#include "base/macros.h"
+#include "base/memory/weak_ptr.h"
+#include "base/task_scheduler/task_traits.h"
+#include "chrome/browser/conflicts/module_info_win.h"
+
+// This class is responsible for inspecting modules on a blocking task runner.
+// For each ModuleInfoKey added, a populated ModuleInfoData will get posted back
+// to the delegate.

[chrisha, 2017/03/01 16:03:38]

Prefer callback to delegate?

[Patrick Monette, 2017/03/03 22:16:30]

Done.

+//
+// The inspection of all modules is quite expensive in terms of resources, so it
+// is done one by one, in a task with a background priority level. If needed, it
+// is possible to increase the priority level of these task by calling

[chrisha, 2017/03/01 16:03:38]

these tasks*

[Patrick Monette, 2017/03/03 22:16:30]

Done.

+// IncreaseInspectionPriority().

[chrisha, 2017/03/01 16:03:38]

Can you comment on the threading model? That this class doesn't provide locking,
and the expectations on what gets called where? On what thread will the
callbacks be posted? etc

[Patrick Monette, 2017/03/03 22:16:29]

Done.

+class ModuleInspector {
+ public:
+  class Delegate {
+   public:
+    // Called when a module has finished being inspectedé
+    virtual void OnModuleInspected(const ModuleInfoKey& module_key,
+                                   const ModuleInfoData& module_data) = 0;
+  };
+
+  explicit ModuleInspector(Delegate* delegate);
+  ~ModuleInspector();
+
+  // Adds the module to the queue of modules to inspect. Starts the inspection
+  // process if the |queue_| is empty.
+  void AddModule(const ModuleInfoKey& module_key);
+
+  // Removes the throttling.
+  void IncreaseInspectionPriority();
+
+ private:
+  // Starts inspecting the module at the front of the queue.
+  void StartInspectingModule();

[chrisha, 2017/03/01 16:03:38]

StartInspectingModules? (plural)

This will kick off inspection of all queued modules, not just the first one.

[Patrick Monette, 2017/03/03 22:16:30]

I'd leave it as-is. This gets called once per module, and it's not part of the
public API.

+
+  // Called back on the execution context on which the ModuleInspector was
+  // created when a module has finished being inspected. The delegate will be
+  // notified and, if the |queue_| is not empty, the next module will be sent
+  // for inspection.
+  void OnInspectionFinished(const ModuleInfoKey& module_key,
+                            const ModuleInfoData& module_data);
+
+  Delegate* delegate_;
+
+  // The modules are put in queue until they get are sent for inspection.
+  std::queue<ModuleInfoKey> queue_;
+
+  // The traits used on the task that inspects the modules. It originally start

[chrisha, 2017/03/01 16:03:38]

starts*

[Patrick Monette, 2017/03/03 22:16:30]

Done.

+  // at a BACKGROUND priority, but is changed to USER_VISIBLE when
+  // IncreaseInspectionPriority() is called.
+  base::TaskTraits inspection_task_traits_;

[chrisha, 2017/03/01 16:03:38]

+1 to using the new task scheduler!

[Patrick Monette, 2017/03/03 22:16:30]

Works great!

+
+  // The vector of paths to %env_var%, used to account for differences in
+  // where people keep there files, c:\windows vs. d:\windows, etc.

[chrisha, 2017/03/01 16:03:38]

their*

... and localization

[Patrick Monette, 2017/03/03 22:16:30]

Done.

+  StringMapping path_mapping_;
+
+  // Weak pointers are used to safely post the inspection result back to the
+  // ModuleInspector from the task scheduler.
+  base::WeakPtrFactory<ModuleInspector> weak_ptr_factory_;
+
+  DISALLOW_COPY_AND_ASSIGN(ModuleInspector);
+};
+
+#endif  // CHROME_BROWSER_CONFLICTS_MODULE_INSPECTOR_WIN_H_