Bug 1548569 - Fire event from ADB track-devices to unblock aboutdebugging initialization r=Ola

Differential Revision: https://phabricator.services.mozilla.com/D29675

--HG--
extra : moz-landing-system : lando

devtools/shared/adb/adb.js

@@ -33,9 +33,11 @@ class Adb extends EventEmitter {
     this._updateAdbProcess = this._updateAdbProcess.bind(this);
     this._onDeviceConnected = this._onDeviceConnected.bind(this);
     this._onDeviceDisconnected = this._onDeviceDisconnected.bind(this);
+    this._onNoDevicesDetected = this._onNoDevicesDetected.bind(this);
 
     this._trackDevicesCommand.on("device-connected", this._onDeviceConnected);
     this._trackDevicesCommand.on("device-disconnected", this._onDeviceDisconnected);
+    this._trackDevicesCommand.on("no-devices-detected", this._onNoDevicesDetected);
     adbAddon.on("update", this._updateAdbProcess);
   }
 
@@ -126,6 +128,10 @@ class Adb extends EventEmitter {
     this.updateRuntimes();
   }
 
+  _onNoDevicesDetected() {
+    this.updateRuntimes();
+  }
+
   async _getDeviceRuntimes(device) {
     const socketPaths = [...await device.getRuntimeSocketPaths()];
     return socketPaths.map(socketPath => new AdbRuntime(device, socketPath));

devtools/shared/adb/commands/track-devices.js

@@ -123,9 +123,14 @@ class TrackDevicesCommand extends EventEmitter {
   }
 
   _disconnectAllDevices() {
-    for (const [deviceId, status] of this._devices.entries()) {
-      if (status !== ADB_STATUS_OFFLINE) {
-        this.emit("device-disconnected", deviceId);
+    if (this._devices.size === 0) {
+      // If no devices were detected, fire an event to let consumer resume.
+      this.emit("no-devices-detected");
+    } else {
+      for (const [deviceId, status] of this._devices.entries()) {
+        if (status !== ADB_STATUS_OFFLINE) {
+          this.emit("device-disconnected", deviceId);
+        }
       }
     }
     this._devices = new Map();