TabManager: Add more logs to understand how it works when memory is low.

chrome/browser/chromeos/arc/process/arc_process.cc

 // 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.
 
 #include "chrome/browser/chromeos/arc/process/arc_process.h"
 
 #include <utility>
 
 namespace arc {
 
@@ skipping 27 matching lines @@
   return process_state() <= mojom::ProcessState::IMPORTANT_FOREGROUND;
 }
 
 bool ArcProcess::IsKernelKillable() const {
   // Protect PERSISTENT, PERSISTENT_UI, and our HOME processes since they should
   // never be killed even by the kernel. Returning false for them allows their
   // OOM adjustment scores to remain negative.
   return process_state() > arc::mojom::ProcessState::PERSISTENT_UI;
 }
 
+std::ostream& operator<<(std::ostream& out, const ArcProcess& arc_process) {
+  out << "Arc process " << arc_process.process_name() << " ("

[Yusuke Sato, 2017/05/18 21:42:49]

nit: it might be unclear that the number inside the paren is a PID. What about
"just" dump everything?

 out << "process_name: " << arc_process.process_name() << ", pid: " <<
arc_process.pid()

[cylee1, 2017/05/18 22:11:06]

Done.

+      << arc_process.pid() << ")"
+      << ", process_state: " << arc_process.process_state()
+      << ", is_focused: " << arc_process.is_focused()
+      << ", last_activity_time: " << arc_process.last_activity_time()
+      << ", packages: ";
+  for (const auto pkg : arc_process.packages())
+    out << pkg << ",";

[Yusuke Sato, 2017/05/18 21:42:49]

The last "," seems redundant.

 #include "base/strings/string_util.h"

then

 << ", packages: " << base::JoinString(arc_process.packages(), ",");

(or using " " as a separator) would be better.

[cylee1, 2017/05/18 22:11:05]

thanks ! haven't work on the code base for a while so forget the util library ..

+  return out;
+}
+
 }  // namespace arc