Show all system process in the task_manager.

chrome/browser/chromeos/arc/arc_process_service.cc

Index: chrome/browser/chromeos/arc/arc_process_service.cc
diff --git a/chrome/browser/chromeos/arc/arc_process_service.cc b/chrome/browser/chromeos/arc/arc_process_service.cc
index e8dc49b233a105ad26ed335c91a86db621210a8d..d8379157137c8aed62079549d956e59c752ecca1 100644
--- a/chrome/browser/chromeos/arc/arc_process_service.cc
+++ b/chrome/browser/chromeos/arc/arc_process_service.cc
@@ -77,7 +77,48 @@ void ArcProcessService::Reset() {
   nspid_to_pid_.clear();
 }
 
-bool ArcProcessService::RequestProcessList(
+bool ArcProcessService::RequestSystemProcessList(

[cylee1, 2016/06/02 20:58:45]

nit: can you try to consolidate the logic here and in OnReceiveProcessList ?
For example, creating a function like PostTaskToOwnThreadAndReply(task,
callback).

[Hsu-Cheng, 2016/06/29 10:33:57]

Done.

+    RequestProcessListCallback callback) {
+  DCHECK_CURRENTLY_ON(content::BrowserThread::UI);
+
+  auto ret_processes = new vector<ArcProcess>();
+  auto runner = worker_pool_->GetSequencedTaskRunner(

[Yusuke Sato, 2016/06/02 21:50:11]

Why does this have to be sequenced, btw?

[Hsu-Cheng, 2016/06/29 10:33:57]

The pool size here is 1 and this is for avoid running delayed jobs at the same
time. 

+      worker_pool_->GetNamedSequenceToken(kSequenceToken));
+  runner->PostTaskAndReply(
+      FROM_HERE, base::Bind(&ArcProcessService::FetchAndReturnSystemProcessList,
+                            weak_ptr_factory_.GetWeakPtr(),
+                            base::Unretained(ret_processes)),
+      base::Bind(&ArcProcessService::CallbackRelay,
+                 weak_ptr_factory_.GetWeakPtr(), callback,
+                 base::Owned(ret_processes)));
+  return true;

[cylee1, 2016/06/02 20:58:45]

Always return true?

[Hsu-Cheng, 2016/06/29 10:33:57]

Done.

+}
+
+void ArcProcessService::FetchAndReturnSystemProcessList(

[cylee1, 2016/06/02 20:58:44]

Maybe GetArcSystemProcessList

[Hsu-Cheng, 2016/06/29 10:33:57]

Done.

+    vector<ArcProcess>* ret_processes) {
+  DCHECK(thread_checker_.CalledOnValidThread());
+
+  const base::ProcessIterator::ProcessEntries& entry_list =
+      base::ProcessIterator(nullptr).Snapshot();
+  ProcessId arc_init_pid = GetArcInitProcessId(entry_list);

[cylee1, 2016/06/02 20:58:45]

You should check if it's kNullProcessId before doing the next step.

[Hsu-Cheng, 2016/06/29 10:33:56]

Done.

+
+  // Enumerate the child processes of ARC init for gaterhing ARC system procces

[cylee1, 2016/06/02 20:58:44]

nit: gathering
nit: processes

I think you should add comment somewhere to note your definition of "system
process" is "direct children of init process" and why so.

[Hsu-Cheng, 2016/06/29 10:33:57]

Added system process definition in arc_process_service.h 

+  for (const base::ProcessEntry& entry : entry_list) {
+    std::string process_name =

[cylee1, 2016/06/02 20:58:44]

why not get process_name inside the if at line 109?

[Hsu-Cheng, 2016/06/29 10:33:57]

Done.

+        !entry.cmd_line_args().empty() ? entry.cmd_line_args()[0] : "";
+    if (entry.parent_pid() == arc_init_pid) {

[Yusuke Sato, 2016/06/02 21:50:11]

This will only detect direct children of the init process, right? Is that good
enough? For example, installd might fork/execute dex2oat which might take a few
minutes to finish worst case, but with this logic, the dex2oat process won't
show up in Task Manager.

[Hsu-Cheng, 2016/06/29 10:33:57]

You are right. I miss the case. I will make a new change for this. TODO is
added.

+      ProcessId child_pid = entry.pid();
+      ProcessId child_nspid = base::Process(child_pid).GetPidInNamespace();
+      if (child_nspid != kNullProcessId) {
+        ArcProcess arc_process = {child_nspid, child_pid, process_name,

[Yusuke Sato, 2016/06/02 21:50:11]

This no longer compiles once you rebase your Chromium copy to tot because
r397310 made ArcProcess move-only.

 ArcProcess arc_process(child_nspid, child_pid, process_name,
mojom::ProcessState::PERSISTENT);
 ret_processes->push_back(std::move(arc_process));

[Hsu-Cheng, 2016/06/29 10:33:57]

Done.

+                                  mojom::ProcessState::PERSISTENT};
+        ret_processes->push_back(arc_process);
+      }
+    }
+  }
+}
+
+bool ArcProcessService::RequestAppProcessList(
     RequestProcessListCallback callback) {
   DCHECK_CURRENTLY_ON(content::BrowserThread::UI);
 
@@ -201,16 +242,7 @@ void ArcProcessService::UpdateNspidToPidMap() {
     process_tree[entry.parent_pid()].push_back(entry.pid());
 
   // Find the ARC init process.
-  ProcessId arc_init_pid = kNullProcessId;
-  for (const base::ProcessEntry& entry : entry_list) {
-    // TODO(nya): Add more constraints to avoid mismatches.
-    std::string process_name =
-        !entry.cmd_line_args().empty() ? entry.cmd_line_args()[0] : "";
-    if (process_name == "/init") {
-      arc_init_pid = entry.pid();
-      break;
-    }
-  }
+  ProcessId arc_init_pid = GetArcInitProcessId(entry_list);
 
   // Enumerate all processes under ARC init and create nspid -> pid map.
   if (arc_init_pid != kNullProcessId) {
@@ -241,4 +273,18 @@ void ArcProcessService::UpdateNspidToPidMap() {
   }
 }
 
+ProcessId ArcProcessService::GetArcInitProcessId(
+    const base::ProcessIterator::ProcessEntries& entry_list) {
+  // Find the ARC init process.
+  for (const base::ProcessEntry& entry : entry_list) {
+    // TODO(nya): Add more constraints to avoid mismatches.
+    std::string process_name =
+        !entry.cmd_line_args().empty() ? entry.cmd_line_args()[0] : "";
+    if (process_name == "/init") {
+      return entry.pid();
+    }
+  }
+  return kNullProcessId;
+}
+
 }  // namespace arc