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

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

Index: chrome/browser/chromeos/arc/process/arc_process.cc
diff --git a/chrome/browser/chromeos/arc/process/arc_process.cc b/chrome/browser/chromeos/arc/process/arc_process.cc
index fbb8d7c37930dedffa96818be60a0726e8723edb..8268de434b2b4cbc9442fb2f34a9de0bb91c71be 100644
--- a/chrome/browser/chromeos/arc/process/arc_process.cc
+++ b/chrome/browser/chromeos/arc/process/arc_process.cc
@@ -6,6 +6,8 @@
 
 #include <utility>
 
+#include "base/strings/string_util.h"
+
 namespace arc {
 
 ArcProcess::ArcProcess(base::ProcessId nspid,
@@ -45,4 +47,14 @@ bool ArcProcess::IsKernelKillable() const {
   return process_state() > arc::mojom::ProcessState::PERSISTENT_UI;
 }
 
+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