Show all system process in the task_manager.

chrome/browser/chromeos/arc/arc_process_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_CHROMEOS_ARC_ARC_PROCESS_SERVICE_H_
 #define CHROME_BROWSER_CHROMEOS_ARC_ARC_PROCESS_SERVICE_H_
 
 #include <map>
 #include <vector>
 
-#include "base/callback.h"
+#include "base/callback_forward.h"
+#include "base/macros.h"
 #include "base/memory/ref_counted.h"
 #include "base/memory/weak_ptr.h"
+#include "base/process/process_iterator.h"
 #include "base/threading/sequenced_worker_pool.h"
 #include "base/threading/thread_checker.h"
 #include "chrome/browser/chromeos/arc/arc_process.h"
 #include "components/arc/arc_bridge_service.h"
 #include "components/arc/arc_service.h"
 
 namespace arc {
 
 // A single global entry to get a list of ARC processes.
 //
-// Call RequestProcessList() on the main UI thread to get a list of all ARC
-// processes. It returns vector<arc::ArcProcess>, which includes pid <-> nspid
-// mapping.
+// Call RequestAppProcessList() / RequestSystemProcessList() on the main UI
+// thread to get a list of all ARC app / system processes. It returns
+// vector<arc::ArcProcess>, which includes pid <-> nspid mapping.
 // Example:
 //   void OnUpdateProcessList(const vector<arc::ArcProcess>&) {...}
 //
 //   arc::ArcProcessService* arc_process_service =
 //       arc::ArcProcessService::Get();
 //   if (!arc_process_service ||
-//       !arc_process_service->RequestProcessList(
+//       !arc_process_service->RequestAppProcessList(
 //           base::Bind(&OnUpdateProcessList)) {
 //     LOG(ERROR) << "ARC process instance not ready.";
 //   }
+//
+// [System Process]
+// The system process here is defined by the scope. If the process is produced
+// under system_server in Android, we regard it as one of Android app process.
+// Otherwise, the processes that are introduced by init would then be regarded
+// as System Process. RequestAppProcessList() is responsible for app processes
+// while RequestSystemProcessList() is responsible for System Processes.
 class ArcProcessService : public ArcService,
-                          public ArcBridgeService::Observer {
+                          public ArcBridgeService::Observer,
+                          public base::RefCountedThreadSafe<ArcProcessService> {

[Luis Héctor Chávez, 2016/07/06 19:49:15]

This is a bit problematic, since RefCounted needs your destructor to be private
to avoid the object going away while there are still active references
around[1]. The problem is that making the destructor private makes it ineligible
for using it in an unique_ptr :'(

Here's my original suggestion:

class ArcProcessService : ... {
...
private:
class ProcessList : public base::RefcountedThreadSafe<ProcessList> {
 public:
  std::vector<ArcProcess> UpdateAndReturnProcessList(
    const std::vector<ArcProcess>& raw_processes);

 private:
  ~ProcessList();
  ...
  std::map<base::ProcessId, base::ProcessId> nspid_to_pid_;

  DISALLOW_COPY_AND_ASSIGN(ProcessList);
};

scoped_refptr<ProcessList> process_list_;
};

That way the outside class can still be wrapped in an unique_ptr and the
|nspid_to_pid_| map is safely used in only one thread.

1:
https://cs.chromium.org/chromium/src/base/memory/ref_counted.h?q=base::RefCou...

  public:
   using RequestProcessListCallback =
       base::Callback<void(const std::vector<ArcProcess>&)>;
 
   explicit ArcProcessService(ArcBridgeService* bridge_service);
   ~ArcProcessService() override;
 
   // Returns nullptr before the global instance is ready.
   static ArcProcessService* Get();
 
   // ArcBridgeService::Observer overrides.
   void OnProcessInstanceReady() override;
 
   // Returns true if ARC IPC is ready for process list request,
   // otherwise false.
-  bool RequestProcessList(RequestProcessListCallback callback);
+  bool RequestAppProcessList(RequestProcessListCallback callback);
+  void RequestSystemProcessList(RequestProcessListCallback callback);
 
  private:
   void Reset();
 
   void OnReceiveProcessList(
       const RequestProcessListCallback& callback,
       mojo::Array<arc::mojom::RunningAppProcessInfoPtr> mojo_processes);
 
-  void CallbackRelay(
-      const RequestProcessListCallback& callback,
-      const std::vector<ArcProcess>* ret_processes);
+  std::vector<ArcProcess> UpdateAndReturnProcessList(
+      const std::vector<ArcProcess>& raw_processes);
 
-  void UpdateAndReturnProcessList(
-      const std::vector<arc::mojom::RunningAppProcessInfoPtr>* raw_processes,
-      std::vector<ArcProcess>* ret_processes);
+  std::vector<ArcProcess> PopulateProcessList(
+      const std::vector<ArcProcess>& raw_processes);
 
-  void PopulateProcessList(
-      const std::vector<arc::mojom::RunningAppProcessInfoPtr>* raw_processes,
-      std::vector<ArcProcess>* ret_processes);
+  std::vector<ArcProcess> ConvertMojoProcess(
+      mojo::Array<arc::mojom::RunningAppProcessInfoPtr>& mojo_processes);
 
   void UpdateNspidToPidMap();
 
+  static std::vector<ArcProcess> GetArcSystemProcessList();

[Luis Héctor Chávez, 2016/07/06 20:28:12]

Prefer having these two in the anonymous namespace in the .cc file

+
+  static base::ProcessId GetArcInitProcessId(
+      const base::ProcessIterator::ProcessEntries& entry_list);
+
   // Keep a cache pid mapping of all arc processes so to minimize the number of
   // nspid lookup from /proc/<PID>/status.
   // To play safe, always modify |nspid_to_pid_| on the worker thread.
   std::map<base::ProcessId, base::ProcessId> nspid_to_pid_;
 
   scoped_refptr<base::SequencedWorkerPool> worker_pool_;
 
   // To ensure internal state changes are done on the same worker thread.
   base::ThreadChecker thread_checker_;
 
   // Always keep this the last member of this class to make sure it's the
   // first thing to be destructed.
   base::WeakPtrFactory<ArcProcessService> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(ArcProcessService);
 };
 
 }  // namespace arc
 
 #endif  // CHROME_BROWSER_CHROMEOS_ARC_ARC_PROCESS_SERVICE_H_