Refactor ARC OOM handler code

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 {
 
+namespace {
+
+// A special process on Android side which serves as a dummy "focused" app

[Yusuke Sato, 2017/05/09 22:54:35]

moved

+// when the focused window is a Chrome side window (i.e., all Android
+// processes are running in the background). We don't want to kill it anyway.
+static constexpr char kArcHomeProcess[] = "org.chromium.arc.home";

[Luis Héctor Chávez, 2017/05/09 23:00:10]

nit: static is superfluous in the anonymous namespace

[Yusuke Sato, 2017/05/09 23:20:12]

Done.

+
+}  // namespace
+
 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;
 
+bool ArcProcess::IsUserVisible() const {
+  return process_state() <= mojom::ProcessState::IMPORTANT_FOREGROUND ||
+         process_name() == kArcHomeProcess;
+}
+
+bool ArcProcess::IsKillableForKernel() 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 &&
+         process_name() != kArcHomeProcess;
+}
+
 }  // namespace arc