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>
 
+#include "base/strings/string_util.h"
+
 namespace arc {
 
 ArcProcess::ArcProcess(base::ProcessId nspid,
                        base::ProcessId pid,
                        const std::string& process_name,
                        mojom::ProcessState process_state,
                        bool is_focused,
                        int64_t last_activity_time)
     : nspid_(nspid),
       pid_(pid),
       process_name_(process_name),
       process_state_(process_state),
       is_focused_(is_focused),
       last_activity_time_(last_activity_time) {}
 
 ArcProcess::~ArcProcess() = default;
 
 // Sort by (process_state, last_activity_time) pair.
 // Smaller process_state value means higher priority as defined in Android.
 // Larger last_activity_time means more recently used.
 bool ArcProcess::operator<(const ArcProcess& rhs) const {
   return std::make_pair(process_state(), -last_activity_time()) <
          std::make_pair(rhs.process_state(), -rhs.last_activity_time());
 }
 
 ArcProcess::ArcProcess(ArcProcess&& other) = default;
 ArcProcess& ArcProcess::operator=(ArcProcess&& other) = default;
 
+std::ostream& operator<<(std::ostream& out, const ArcProcess& arc_process) {
+  out << "process_name: " << arc_process.process_name()
+      << ", pid: " << arc_process.pid()
+      << ", process_state: " << arc_process.process_state()
+      << ", is_focused: " << arc_process.is_focused()
+      << ", last_activity_time: " << arc_process.last_activity_time()
+      << ", packages: " << base::JoinString(arc_process.packages(), ",");
+  return out;
+}
+
 }  // namespace arc