feat(Amplitude): Set device id from cookie. (#4997)

react/features/analytics/handlers/AmplitudeHandler.js

         };
 
         amplitude.getInstance(this._amplitudeOptions).init(amplitudeAPPKey, undefined, { includeReferrer: true });
+        amplitude.fixDeviceID(this._amplitudeOptions);
 
         if (user) {
             amplitude.getInstance(this._amplitudeOptions).setUserId(user);

react/features/analytics/handlers/amplitude/Amplitude.native.js

         }
 
         return instance;
-    }
+    },
+
+    /**
+     * Currently not implemented.
+     *
+     * @returns {void}
+     */
+    fixDeviceID() { } // eslint-disable-line no-empty-function
 };

react/features/analytics/handlers/amplitude/Amplitude.web.js

 import amplitude from 'amplitude-js';
 
 export default {
+    /**
+     * Returns the AmplitudeClient instance.
+     *
+     * @param {Object} options - Optional parameters.
+     * @property {string} options.instanceName - The name of the AmplitudeClient instance.
+     * @returns {AmplitudeClient}
+     */
     getInstance(options = {}) {
         return amplitude.getInstance(options.instanceName);
+    },
+
+    /**
+     * Sets the device id to the value of __AMDID cookie or sets the __AMDID cookie value to the current device id in
+     * case the __AMDID cookie is not set.
+     *
+     * @param {*} options - Optional parameters.
+     * @property {string} options.instanceName - The name of the AmplitudeClient instance.
+     * @property {string} options.host - The host from the original URL.
+     * @returns {void}
+     */
+    fixDeviceID(options) {
+        const deviceId = document.cookie.replace(/(?:(?:^|.*;\s*)__AMDID\s*=\s*([^;]*).*$)|^.*$/, '$1');
+        const instance = this.getInstance(options);
+
+        if (deviceId === '') {
+            const { host = '' } = options;
+
+            document.cookie
+                = `__AMDID=${instance.options.deviceId};max-age=630720000${
+                    host === '' ? '' : `;domain=.${host}`}`; // max-age=10 years
+        } else {
+            instance.setDeviceId(deviceId);
+        }
     }
 };