Replace all manual pluginKey parsing with a utility

Summary:
Ok this diff got a bit bigger than expected, but I think it makes it easier to understand what "plugin keys" are, and makes them less prone to error.

Previously pluginKeys were composed of: clientId#pluginName, where clientId was itself: app#os#device#device_id

But also, there were some plugin keys where the clientId was a device_id.

Now you deconstruct a plugin key, and will get a tagged object with type: 'device' or 'client', and the properties that they each have.

There is now no custom parsing of these afaik, let's keep it that way.

Since it took me a while to figure out what all these IDs are, I've documented it a bit in clientUtils.

Reviewed By: passy

Differential Revision: D18811848

fbshipit-source-id: eed2e2b5eedafb9e27900dbcf79a389fcaffae95

src/dispatcher/notifications.tsx

@@ -21,6 +21,7 @@ import {
 } from '../reducers/notifications';
 import {textContent} from '../utils/index';
 import GK from '../fb-stubs/GK';
+import {deconstructPluginKey} from '../utils/clientUtils';
 
 type NotificationEvents = 'show' | 'click' | 'close' | 'reply' | 'action';
 const NOTIFICATION_THROTTLE = 5 * 1000; // in milliseconds
@@ -106,18 +107,18 @@ export default (store: Store, logger: Logger) => {
     Object.keys(pluginStates).forEach(key => {
       if (knownPluginStates.get(key) !== pluginStates[key]) {
         knownPluginStates.set(key, pluginStates[key]);
-        const split = key.split('#');
-        const pluginId = split.pop();
-        const client = split.join('#');
+        const plugin = deconstructPluginKey(key);
+        const pluginName = plugin.pluginName;
+        const client = plugin.client;
 
-        if (!pluginId) {
+        if (!pluginName) {
           return;
         }
 
         const persistingPlugin:
           | undefined
           | typeof FlipperPlugin
-          | typeof FlipperDevicePlugin = pluginMap.get(pluginId);
+          | typeof FlipperDevicePlugin = pluginMap.get(pluginName);
         if (persistingPlugin && persistingPlugin.getActiveNotifications) {
           store.dispatch(
             setActiveNotifications({
@@ -125,7 +126,7 @@ export default (store: Store, logger: Logger) => {
                 pluginStates[key],
               ),
               client,
-              pluginId,
+              pluginId: pluginName,
             }),
           );
         }