TabManagerDelegate: Better prioritize ARC processes.

chrome/browser/chromeos/arc/arc_process.h

 // 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.
 
 #ifndef CHROME_BROWSER_CHROMEOS_ARC_ARC_PROCESS_H_
 #define CHROME_BROWSER_CHROMEOS_ARC_ARC_PROCESS_H_
 
+#include <stdint.h>
 #include <string>
 #include <vector>
 
 #include "base/process/process_handle.h"
 #include "components/arc/common/process.mojom.h"
 
 namespace arc {
 
 class ArcProcess {
  public:
   ArcProcess(base::ProcessId nspid,
              base::ProcessId pid,
              const std::string& process_name,
-             mojom::ProcessState process_state);
+             mojom::ProcessState process_state,
+             bool is_focused,
+             int64_t last_activity_time);
   ~ArcProcess();
 
   ArcProcess(ArcProcess&& other);
   ArcProcess& operator=(ArcProcess&& other);
 
+  // Sort by descending importance.
+  bool operator<(const ArcProcess& rhs) const;
+
   base::ProcessId nspid() const { return nspid_; }
   base::ProcessId pid() const { return pid_; }
   const std::string& process_name() const { return process_name_; }
   mojom::ProcessState process_state() const { return process_state_; }
+  bool is_focused() const { return is_focused_; }
+  int64_t last_activity_time() const { return last_activity_time_; }
   std::vector<std::string>& packages() { return packages_; }
   const std::vector<std::string>& packages() const { return packages_; }
 
  private:
   base::ProcessId nspid_;
   base::ProcessId pid_;
   std::string process_name_;
   mojom::ProcessState process_state_;
+  // If the Android app is the focused window.
+  bool is_focused_;
+  // A monotonic timer recording the last time this process was active.
+  // Milliseconds since Android boot. This info is passed from Android
+  // ActivityManagerService via IPC.
+  int64_t last_activity_time_;
   std::vector<std::string> packages_;
 
   DISALLOW_COPY_AND_ASSIGN(ArcProcess);
 };
 
 }  // namespace arc
 
 #endif  // CHROME_BROWSER_CHROMEOS_ARC_ARC_PROCESS_H_