diff --git a/devtools/client/aboutdebugging-new/src/modules/runtime-client-factory.js b/devtools/client/aboutdebugging-new/src/modules/runtime-client-factory.js
index 3a6237e37958..8a198ae243c9 100644
--- a/devtools/client/aboutdebugging-new/src/modules/runtime-client-factory.js
+++ b/devtools/client/aboutdebugging-new/src/modules/runtime-client-factory.js
@@ -4,7 +4,7 @@
 
 "use strict";
 
-const { ADB } = require("devtools/shared/adb/adb");
+const { prepareTCPConnection } = require("devtools/shared/adb/commands/index");
 const { DebuggerClient } = require("devtools/shared/client/debugger-client");
 const { DebuggerServer } = require("devtools/server/main");
 const { ClientWrapper } = require("./client-wrapper");
@@ -29,7 +29,7 @@ async function createNetworkClient(host, port) {
 }
 
 async function createUSBClient(socketPath) {
-  const port = await ADB.prepareTCPConnection(socketPath);
+  const port = await prepareTCPConnection(socketPath);
   return createNetworkClient("localhost", port);
 }
 
diff --git a/devtools/shared/adb/adb-device.js b/devtools/shared/adb/adb-device.js
index dc52b4b57920..9abfa79e3965 100644
--- a/devtools/shared/adb/adb-device.js
+++ b/devtools/shared/adb/adb-device.js
@@ -4,7 +4,7 @@
 
 "use strict";
 
-const { ADB } = require("devtools/shared/adb/adb");
+const { shell } = require("devtools/shared/adb/commands/index");
 
 /**
  * A Device instance is created and registered with the Devices module whenever
@@ -19,7 +19,7 @@ class AdbDevice {
     if (this._model) {
       return this._model;
     }
-    const model = await ADB.shell("getprop ro.product.model");
+    const model = await shell("getprop ro.product.model");
     this._model = model.trim();
     return this._model;
   }
@@ -33,7 +33,7 @@ class AdbDevice {
     // 00000000: 00000002 00000000 00010000 0001 01 6551588
     //  /data/data/org.mozilla.fennec/firefox-debugger-socket
     const query = "cat /proc/net/unix";
-    const rawSocketInfo = await ADB.shell(query);
+    const rawSocketInfo = await shell(query);
 
     // Filter to lines with "firefox-debugger-socket"
     let socketInfos = rawSocketInfo.split(/\r?\n/);
diff --git a/devtools/shared/adb/adb-runtime.js b/devtools/shared/adb/adb-runtime.js
index 2809a241cdfc..e6f7dcde047d 100644
--- a/devtools/shared/adb/adb-runtime.js
+++ b/devtools/shared/adb/adb-runtime.js
@@ -5,7 +5,7 @@
 "use strict";
 
 const { RuntimeTypes } = require("devtools/client/webide/modules/runtime-types");
-const { ADB } = require("devtools/shared/adb/adb");
+const { prepareTCPConnection } = require("devtools/shared/adb/commands/index");
 
 class AdbRuntime {
   constructor(adbDevice, model, socketPath) {
@@ -33,7 +33,7 @@ class AdbRuntime {
   }
 
   connect(connection) {
-    return ADB.prepareTCPConnection(this._socketPath).then(port => {
+    return prepareTCPConnection(this._socketPath).then(port => {
       connection.host = "localhost";
       connection.port = port;
       connection.connect();
diff --git a/devtools/shared/adb/adb-scanner.js b/devtools/shared/adb/adb-scanner.js
index 285ae781f504..9a382c65f054 100644
--- a/devtools/shared/adb/adb-scanner.js
+++ b/devtools/shared/adb/adb-scanner.js
@@ -7,6 +7,7 @@
 const EventEmitter = require("devtools/shared/event-emitter");
 const { dumpn } = require("devtools/shared/DevToolsUtils");
 const { ADB } = require("devtools/shared/adb/adb");
+const { trackDevices } = require("devtools/shared/adb/commands/index");
 const { adbDevicesRegistry } = require("devtools/shared/adb/adb-devices-registry");
 const { AdbRuntime } = require("devtools/shared/adb/adb-runtime");
 
@@ -30,7 +31,7 @@ class ADBScanner extends EventEmitter {
     adbDevicesRegistry.on("unregister", this._updateRuntimes);
 
     ADB.start().then(() => {
-      ADB.trackDevices();
+      trackDevices();
     });
     this._updateRuntimes();
   }
diff --git a/devtools/shared/adb/adb.js b/devtools/shared/adb/adb.js
index dc9d1ba3d319..46b252e68cb4 100644
--- a/devtools/shared/adb/adb.js
+++ b/devtools/shared/adb/adb.js
@@ -7,21 +7,17 @@
 "use strict";
 
 const { Cc, Ci } = require("chrome");
-const EventEmitter = require("devtools/shared/event-emitter");
-const client = require("./adb-client");
 const { dumpn } = require("devtools/shared/DevToolsUtils");
 const { getFileForBinary } = require("./adb-binary");
 const { setTimeout } = require("resource://gre/modules/Timer.jsm");
 const { Services } = require("resource://gre/modules/Services.jsm");
-const { ConnectionManager } = require("devtools/shared/client/connection-manager");
+const { runCommand } = require("./commands/index");
 loader.lazyRequireGetter(this, "check",
                          "devtools/shared/adb/adb-running-checker", true);
 
 let ready = false;
 let didRunInitially = false;
 
-const OKAY = 0x59414b4f;
-
 const ADB = {
   get didRunInitially() {
     return didRunInitially;
@@ -137,7 +133,7 @@ const ADB = {
    */
   async kill() {
     try {
-      await this.runCommand("host:kill");
+      await runCommand("host:kill");
     } catch (e) {
       dumpn("Failed to send host:kill command");
     }
@@ -145,280 +141,6 @@ const ADB = {
     this.ready = false;
     this.didRunInitially = false;
   },
-
-  // Start tracking devices connecting and disconnecting from the host.
-  // We can't reuse runCommand here because we keep the socket alive.
-  // @return The socket used.
-  trackDevices() {
-    dumpn("trackDevices");
-    const socket = client.connect();
-    let waitForFirst = true;
-    const devices = {};
-
-    socket.s.onopen = function() {
-      dumpn("trackDevices onopen");
-      Services.obs.notifyObservers(null, "adb-track-devices-start");
-      const req = client.createRequest("host:track-devices");
-      socket.send(req);
-    };
-
-    socket.s.onerror = function(event) {
-      dumpn("trackDevices onerror: " + event);
-      Services.obs.notifyObservers(null, "adb-track-devices-stop");
-    };
-
-    socket.s.onclose = function() {
-      dumpn("trackDevices onclose");
-
-      // Report all devices as disconnected
-      for (const dev in devices) {
-        devices[dev] = false;
-        EventEmitter.emit(ADB, "device-disconnected", dev);
-      }
-
-      Services.obs.notifyObservers(null, "adb-track-devices-stop");
-
-      // When we lose connection to the server,
-      // and the adb is still on, we most likely got our server killed
-      // by local adb. So we do try to reconnect to it.
-      setTimeout(function() { // Give some time to the new adb to start
-        if (ADB.ready) { // Only try to reconnect/restart if the add-on is still enabled
-          ADB.start().then(function() { // try to connect to the new local adb server
-                                         // or, spawn a new one
-            ADB.trackDevices(); // Re-track devices
-          });
-        }
-      }, 2000);
-    };
-
-    socket.s.ondata = function(event) {
-      dumpn("trackDevices ondata");
-      const data = event.data;
-      dumpn("length=" + data.byteLength);
-      const dec = new TextDecoder();
-      dumpn(dec.decode(new Uint8Array(data)).trim());
-
-      // check the OKAY or FAIL on first packet.
-      if (waitForFirst) {
-        if (!client.checkResponse(data, OKAY)) {
-          socket.close();
-          return;
-        }
-      }
-
-      const packet = client.unpackPacket(data, !waitForFirst);
-      waitForFirst = false;
-
-      if (packet.data == "") {
-        // All devices got disconnected.
-        for (const dev in devices) {
-          devices[dev] = false;
-          EventEmitter.emit(ADB, "device-disconnected", dev);
-        }
-      } else {
-        // One line per device, each line being $DEVICE\t(offline|device)
-        const lines = packet.data.split("\n");
-        const newDev = {};
-        lines.forEach(function(line) {
-          if (line.length == 0) {
-            return;
-          }
-
-          const [dev, status] = line.split("\t");
-          newDev[dev] = status !== "offline";
-        });
-        // Check which device changed state.
-        for (const dev in newDev) {
-          if (devices[dev] != newDev[dev]) {
-            if (dev in devices || newDev[dev]) {
-              const topic = newDev[dev] ? "device-connected"
-                                        : "device-disconnected";
-              EventEmitter.emit(ADB, topic, dev);
-            }
-            devices[dev] = newDev[dev];
-          }
-        }
-      }
-    };
-  },
-
-  // Sends back an array of device names.
-  listDevices() {
-    dumpn("listDevices");
-
-    return this.runCommand("host:devices").then(
-      function onSuccess(data) {
-        const lines = data.split("\n");
-        const res = [];
-        lines.forEach(function(line) {
-          if (line.length == 0) {
-            return;
-          }
-          const [ device ] = line.split("\t");
-          res.push(device);
-        });
-        return res;
-      }
-    );
-  },
-
-  // sends adb forward localPort devicePort
-  forwardPort(localPort, devicePort) {
-    dumpn("forwardPort " + localPort + " -- " + devicePort);
-    // <host-prefix>:forward:<local>;<remote>
-
-    return this.runCommand("host:forward:" + localPort + ";" + devicePort)
-               .then(function onSuccess(data) {
-                 return data;
-               });
-  },
-
-  // Prepare TCP connection for provided socket path.
-  // The returned value is a port number of localhost for the connection.
-  async prepareTCPConnection(socketPath) {
-    const port = ConnectionManager.getFreeTCPPort();
-    const local = `tcp:${ port }`;
-    const remote = socketPath.startsWith("@")
-                     ? `localabstract:${ socketPath.substring(1) }`
-                     : `localfilesystem:${ socketPath }`;
-    await this.forwardPort(local, remote);
-    return port;
-  },
-
-  // Run a shell command
-  async shell(command) {
-    let state;
-    let stdout = "";
-
-    dumpn("shell " + command);
-
-    return new Promise((resolve, reject) => {
-      const shutdown = function() {
-        dumpn("shell shutdown");
-        socket.close();
-        reject("BAD_RESPONSE");
-      };
-
-      const runFSM = function runFSM(data) {
-        dumpn("runFSM " + state);
-        let req;
-        let ignoreResponseCode = false;
-        switch (state) {
-          case "start":
-            state = "send-transport";
-            runFSM();
-            break;
-          case "send-transport":
-            req = client.createRequest("host:transport-any");
-            socket.send(req);
-            state = "wait-transport";
-            break;
-          case "wait-transport":
-            if (!client.checkResponse(data, OKAY)) {
-              shutdown();
-              return;
-            }
-            state = "send-shell";
-            runFSM();
-            break;
-          case "send-shell":
-            req = client.createRequest("shell:" + command);
-            socket.send(req);
-            state = "rec-shell";
-            break;
-          case "rec-shell":
-            if (!client.checkResponse(data, OKAY)) {
-              shutdown();
-              return;
-            }
-            state = "decode-shell";
-            if (client.getBuffer(data).byteLength == 4) {
-              break;
-            }
-            ignoreResponseCode = true;
-            // eslint-disable-next-lined no-fallthrough
-          case "decode-shell":
-            const decoder = new TextDecoder();
-            const text = new Uint8Array(client.getBuffer(data),
-                                        ignoreResponseCode ? 4 : 0);
-            stdout += decoder.decode(text);
-            break;
-          default:
-            dumpn("shell Unexpected State: " + state);
-            reject("UNEXPECTED_STATE");
-        }
-      };
-
-      const socket = client.connect();
-      socket.s.onerror = function(event) {
-        dumpn("shell onerror");
-        reject("SOCKET_ERROR");
-      };
-
-      socket.s.onopen = function(event) {
-        dumpn("shell onopen");
-        state = "start";
-        runFSM();
-      };
-
-      socket.s.onclose = function(event) {
-        resolve(stdout);
-        dumpn("shell onclose");
-      };
-
-      socket.s.ondata = function(event) {
-        dumpn("shell ondata");
-        runFSM(event.data);
-      };
-    });
-  },
-
-  // Asynchronously runs an adb command.
-  // @param command The command as documented in
-  // http://androidxref.com/4.0.4/xref/system/core/adb/SERVICES.TXT
-  runCommand(command) {
-    dumpn("runCommand " + command);
-    return new Promise((resolve, reject) => {
-      if (!this.ready) {
-        setTimeout(function() {
-          reject("ADB_NOT_READY");
-        });
-        return;
-      }
-
-      const socket = client.connect();
-
-      socket.s.onopen = function() {
-        dumpn("runCommand onopen");
-        const req = client.createRequest(command);
-        socket.send(req);
-      };
-
-      socket.s.onerror = function() {
-        dumpn("runCommand onerror");
-        reject("NETWORK_ERROR");
-      };
-
-      socket.s.onclose = function() {
-        dumpn("runCommand onclose");
-      };
-
-      socket.s.ondata = function(event) {
-        dumpn("runCommand ondata");
-        const data = event.data;
-
-        const packet = client.unpackPacket(data, false);
-        if (!client.checkResponse(data, OKAY)) {
-          socket.close();
-          dumpn("Error: " + packet.data);
-          reject("PROTOCOL_ERROR");
-          return;
-        }
-
-        resolve(packet.data);
-      };
-    });
-  },
 };
 
 exports.ADB = ADB;
diff --git a/devtools/shared/adb/commands/index.js b/devtools/shared/adb/commands/index.js
new file mode 100644
index 000000000000..c88c23551f30
--- /dev/null
+++ b/devtools/shared/adb/commands/index.js
@@ -0,0 +1,19 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+"use strict";
+
+const { listDevices } = require("./list-devices");
+const { prepareTCPConnection } = require("./prepare-tcp-connection");
+const { runCommand } = require("./run-command");
+const { shell } = require("./shell");
+const { trackDevices } = require("./track-devices");
+
+module.exports = {
+  listDevices,
+  prepareTCPConnection,
+  runCommand,
+  shell,
+  trackDevices,
+};
diff --git a/devtools/shared/adb/commands/list-devices.js b/devtools/shared/adb/commands/list-devices.js
new file mode 100644
index 000000000000..bff26622edd3
--- /dev/null
+++ b/devtools/shared/adb/commands/list-devices.js
@@ -0,0 +1,31 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+"use strict";
+
+const { dumpn } = require("devtools/shared/DevToolsUtils");
+/**
+ * The listDevices command is currently unused in DevTools. We are keeping it while
+ * working on RemoteDebugging NG, in case it becomes needed later. We will remove it from
+ * the codebase if unused at the end of the project. See Bug 1511779.
+ */
+const listDevices = function() {
+  dumpn("listDevices");
+
+  return this.runCommand("host:devices").then(
+    function onSuccess(data) {
+      const lines = data.split("\n");
+      const res = [];
+      lines.forEach(function(line) {
+        if (line.length == 0) {
+          return;
+        }
+        const [ device ] = line.split("\t");
+        res.push(device);
+      });
+      return res;
+    }
+  );
+};
+exports.listDevices = listDevices;
diff --git a/devtools/shared/adb/commands/moz.build b/devtools/shared/adb/commands/moz.build
new file mode 100644
index 000000000000..6f2b0f13afc7
--- /dev/null
+++ b/devtools/shared/adb/commands/moz.build
@@ -0,0 +1,12 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+DevToolsModules(
+    'index.js',
+    'list-devices.js',
+    'prepare-tcp-connection.js',
+    'run-command.js',
+    'shell.js',
+    'track-devices.js',
+)
diff --git a/devtools/shared/adb/commands/prepare-tcp-connection.js b/devtools/shared/adb/commands/prepare-tcp-connection.js
new file mode 100644
index 000000000000..c8b7412343ff
--- /dev/null
+++ b/devtools/shared/adb/commands/prepare-tcp-connection.js
@@ -0,0 +1,33 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+"use strict";
+
+const { dumpn } = require("devtools/shared/DevToolsUtils");
+const { ConnectionManager } = require("devtools/shared/client/connection-manager");
+const { runCommand } = require("./run-command");
+
+// sends adb forward localPort devicePort
+const forwardPort = function(localPort, devicePort) {
+  dumpn("forwardPort " + localPort + " -- " + devicePort);
+  // <host-prefix>:forward:<local>;<remote>
+
+  return runCommand("host:forward:" + localPort + ";" + devicePort)
+             .then(function onSuccess(data) {
+               return data;
+             });
+};
+
+// Prepare TCP connection for provided socket path.
+// The returned value is a port number of localhost for the connection.
+const prepareTCPConnection = async function(socketPath) {
+  const port = ConnectionManager.getFreeTCPPort();
+  const local = `tcp:${ port }`;
+  const remote = socketPath.startsWith("@")
+                   ? `localabstract:${ socketPath.substring(1) }`
+                   : `localfilesystem:${ socketPath }`;
+  await forwardPort(local, remote);
+  return port;
+};
+exports.prepareTCPConnection = prepareTCPConnection;
diff --git a/devtools/shared/adb/commands/run-command.js b/devtools/shared/adb/commands/run-command.js
new file mode 100644
index 000000000000..a1c86c5447f5
--- /dev/null
+++ b/devtools/shared/adb/commands/run-command.js
@@ -0,0 +1,62 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+// Wrapper around the ADB utility.
+
+"use strict";
+
+const { dumpn } = require("devtools/shared/DevToolsUtils");
+const { setTimeout } = require("resource://gre/modules/Timer.jsm");
+const { ADB } = require("../adb");
+const client = require("../adb-client");
+
+const OKAY = 0x59414b4f;
+
+// Asynchronously runs an adb command.
+// @param command The command as documented in
+// http://androidxref.com/4.0.4/xref/system/core/adb/SERVICES.TXT
+const runCommand = function(command) {
+  dumpn("runCommand " + command);
+  return new Promise((resolve, reject) => {
+    if (!ADB.ready) {
+      setTimeout(function() {
+        reject("ADB_NOT_READY");
+      });
+      return;
+    }
+
+    const socket = client.connect();
+
+    socket.s.onopen = function() {
+      dumpn("runCommand onopen");
+      const req = client.createRequest(command);
+      socket.send(req);
+    };
+
+    socket.s.onerror = function() {
+      dumpn("runCommand onerror");
+      reject("NETWORK_ERROR");
+    };
+
+    socket.s.onclose = function() {
+      dumpn("runCommand onclose");
+    };
+
+    socket.s.ondata = function(event) {
+      dumpn("runCommand ondata");
+      const data = event.data;
+
+      const packet = client.unpackPacket(data, false);
+      if (!client.checkResponse(data, OKAY)) {
+        socket.close();
+        dumpn("Error: " + packet.data);
+        reject("PROTOCOL_ERROR");
+        return;
+      }
+
+      resolve(packet.data);
+    };
+  });
+};
+exports.runCommand = runCommand;
diff --git a/devtools/shared/adb/commands/shell.js b/devtools/shared/adb/commands/shell.js
new file mode 100644
index 000000000000..3ea2b27d7f8b
--- /dev/null
+++ b/devtools/shared/adb/commands/shell.js
@@ -0,0 +1,101 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+// Wrapper around the ADB utility.
+
+"use strict";
+
+const { dumpn } = require("devtools/shared/DevToolsUtils");
+const client = require("../adb-client");
+
+const OKAY = 0x59414b4f;
+
+const shell = async function(command) {
+  let state;
+  let stdout = "";
+
+  dumpn("shell " + command);
+
+  return new Promise((resolve, reject) => {
+    const shutdown = function() {
+      dumpn("shell shutdown");
+      socket.close();
+      reject("BAD_RESPONSE");
+    };
+
+    const runFSM = function runFSM(data) {
+      dumpn("runFSM " + state);
+      let req;
+      let ignoreResponseCode = false;
+      switch (state) {
+        case "start":
+          state = "send-transport";
+          runFSM();
+          break;
+        case "send-transport":
+          req = client.createRequest("host:transport-any");
+          socket.send(req);
+          state = "wait-transport";
+          break;
+        case "wait-transport":
+          if (!client.checkResponse(data, OKAY)) {
+            shutdown();
+            return;
+          }
+          state = "send-shell";
+          runFSM();
+          break;
+        case "send-shell":
+          req = client.createRequest("shell:" + command);
+          socket.send(req);
+          state = "rec-shell";
+          break;
+        case "rec-shell":
+          if (!client.checkResponse(data, OKAY)) {
+            shutdown();
+            return;
+          }
+          state = "decode-shell";
+          if (client.getBuffer(data).byteLength == 4) {
+            break;
+          }
+          ignoreResponseCode = true;
+          // eslint-disable-next-lined no-fallthrough
+        case "decode-shell":
+          const decoder = new TextDecoder();
+          const text = new Uint8Array(client.getBuffer(data),
+                                      ignoreResponseCode ? 4 : 0);
+          stdout += decoder.decode(text);
+          break;
+        default:
+          dumpn("shell Unexpected State: " + state);
+          reject("UNEXPECTED_STATE");
+      }
+    };
+
+    const socket = client.connect();
+    socket.s.onerror = function(event) {
+      dumpn("shell onerror");
+      reject("SOCKET_ERROR");
+    };
+
+    socket.s.onopen = function(event) {
+      dumpn("shell onopen");
+      state = "start";
+      runFSM();
+    };
+
+    socket.s.onclose = function(event) {
+      resolve(stdout);
+      dumpn("shell onclose");
+    };
+
+    socket.s.ondata = function(event) {
+      dumpn("shell ondata");
+      runFSM(event.data);
+    };
+  });
+};
+
+exports.shell = shell;
diff --git a/devtools/shared/adb/commands/track-devices.js b/devtools/shared/adb/commands/track-devices.js
new file mode 100644
index 000000000000..c927558ef740
--- /dev/null
+++ b/devtools/shared/adb/commands/track-devices.js
@@ -0,0 +1,114 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+// Wrapper around the ADB utility.
+
+"use strict";
+
+const EventEmitter = require("devtools/shared/event-emitter");
+const { dumpn } = require("devtools/shared/DevToolsUtils");
+const { setTimeout } = require("resource://gre/modules/Timer.jsm");
+const { Services } = require("resource://gre/modules/Services.jsm");
+
+const { ADB } = require("../adb");
+const client = require("../adb-client");
+
+const OKAY = 0x59414b4f;
+
+// Start tracking devices connecting and disconnecting from the host.
+// We can't reuse runCommand here because we keep the socket alive.
+// @return The socket used.
+const trackDevices = function() {
+  dumpn("trackDevices");
+  const socket = client.connect();
+  let waitForFirst = true;
+  const devices = {};
+
+  socket.s.onopen = function() {
+    dumpn("trackDevices onopen");
+    Services.obs.notifyObservers(null, "adb-track-devices-start");
+    const req = client.createRequest("host:track-devices");
+    socket.send(req);
+  };
+
+  socket.s.onerror = function(event) {
+    dumpn("trackDevices onerror: " + event);
+    Services.obs.notifyObservers(null, "adb-track-devices-stop");
+  };
+
+  socket.s.onclose = function() {
+    dumpn("trackDevices onclose");
+
+    // Report all devices as disconnected
+    for (const dev in devices) {
+      devices[dev] = false;
+      EventEmitter.emit(ADB, "device-disconnected", dev);
+    }
+
+    Services.obs.notifyObservers(null, "adb-track-devices-stop");
+
+    // When we lose connection to the server,
+    // and the adb is still on, we most likely got our server killed
+    // by local adb. So we do try to reconnect to it.
+    setTimeout(function() { // Give some time to the new adb to start
+      if (ADB.ready) { // Only try to reconnect/restart if the add-on is still enabled
+        ADB.start().then(function() { // try to connect to the new local adb server
+                                       // or, spawn a new one
+          trackDevices(); // Re-track devices
+        });
+      }
+    }, 2000);
+  };
+
+  socket.s.ondata = function(event) {
+    dumpn("trackDevices ondata");
+    const data = event.data;
+    dumpn("length=" + data.byteLength);
+    const dec = new TextDecoder();
+    dumpn(dec.decode(new Uint8Array(data)).trim());
+
+    // check the OKAY or FAIL on first packet.
+    if (waitForFirst) {
+      if (!client.checkResponse(data, OKAY)) {
+        socket.close();
+        return;
+      }
+    }
+
+    const packet = client.unpackPacket(data, !waitForFirst);
+    waitForFirst = false;
+
+    if (packet.data == "") {
+      // All devices got disconnected.
+      for (const dev in devices) {
+        devices[dev] = false;
+        EventEmitter.emit(ADB, "device-disconnected", dev);
+      }
+    } else {
+      // One line per device, each line being $DEVICE\t(offline|device)
+      const lines = packet.data.split("\n");
+      const newDev = {};
+      lines.forEach(function(line) {
+        if (line.length == 0) {
+          return;
+        }
+
+        const [dev, status] = line.split("\t");
+        newDev[dev] = status !== "offline";
+      });
+      // Check which device changed state.
+      for (const dev in newDev) {
+        if (devices[dev] != newDev[dev]) {
+          if (dev in devices || newDev[dev]) {
+            const topic = newDev[dev] ? "device-connected"
+                                      : "device-disconnected";
+            EventEmitter.emit(ADB, topic, dev);
+          }
+          devices[dev] = newDev[dev];
+        }
+      }
+    }
+  };
+};
+exports.trackDevices = trackDevices;
diff --git a/devtools/shared/adb/moz.build b/devtools/shared/adb/moz.build
index f7b23bd92db7..abba6b69e1ca 100644
--- a/devtools/shared/adb/moz.build
+++ b/devtools/shared/adb/moz.build
@@ -2,6 +2,10 @@
 # License, v. 2.0. If a copy of the MPL was not distributed with this
 # file, You can obtain one at http://mozilla.org/MPL/2.0/.
 
+DIRS += [
+    'commands',
+]
+
 DevToolsModules(
     'adb-addon.js',
     'adb-binary.js',
diff --git a/devtools/shared/adb/test/test_adb.js b/devtools/shared/adb/test/test_adb.js
index 910727be13dd..9190d58c5769 100644
--- a/devtools/shared/adb/test/test_adb.js
+++ b/devtools/shared/adb/test/test_adb.js
@@ -9,6 +9,7 @@ const { NetUtil } = require("resource://gre/modules/NetUtil.jsm");
 const { getFileForBinary } = require("devtools/shared/adb/adb-binary");
 const { check } = require("devtools/shared/adb/adb-running-checker");
 const { ADB } = require("devtools/shared/adb/adb");
+const { trackDevices } = require("devtools/shared/adb/commands/index");
 
 const ADB_JSON = {
   "Linux": {
@@ -229,7 +230,7 @@ add_task({
     EventEmitter.on(ADB, "device-connected", deviceId => {
       resolve(deviceId);
     });
-    ADB.trackDevices();
+    trackDevices();
   });
 
   equal(receivedDeviceId, "1234567890");