Update documentation

Author: CrisBarreiro

browser-api/src/main/java/com/duckduckgo/browser/api/WebMessagingBrowserPlugin.kt

@@ -16,8 +16,17 @@
 
 package com.duckduckgo.browser.api
 
+import com.duckduckgo.common.utils.plugins.PluginPoint
 import com.duckduckgo.js.messaging.api.WebMessaging
 
+/**
+ * Interface to provide implementations of [WebMessaging] to the browser, through
+ * [PluginPoint]<[WebMessaging]>
+ */
 interface WebMessagingBrowserPlugin {
+    /**
+     * Provides an implementation of [WebMessaging] to be used by the browser.
+     * @return an instance of [WebMessaging]
+     */
     fun webMessaging(): WebMessaging
 }

js-messaging/js-messaging-api/src/main/java/com/duckduckgo/js/messaging/api/WebMessaging.kt

@@ -19,18 +19,43 @@ package com.duckduckgo.js.messaging.api
 import android.webkit.WebView
 
 interface WebMessaging {
+    /**
+     * Registers the given [jsMessageCallback] to handle messages from the provided [webView].
+     * @param jsMessageCallback the callback to handle incoming messages
+     * @param webView the WebView to register the callback with
+     * Notes:
+     * - It's not recommended to unregister and then register again on the same WebView instance.
+     */
     suspend fun register(
         jsMessageCallback: WebViewCompatMessageCallback,
         webView: WebView,
     )
 
+    /**
+     * Unregisters any previously registered message handlers from the given [webView].
+     * Notes:
+     * - This does not remove the JavaScript interface from the WebView, just the handlers.
+     * - It's not required to call this when the WebView is being destroyed.
+     * - It's not recommended to unregister and then register again on the same WebView instance.
+     * @param webView the WebView to unregister the handlers from
+     */
     suspend fun unregister(webView: WebView)
 
+    /**
+     * Posts a message to the given [webView] using the provided [subscriptionEventData].
+     * @param webView the WebView to which the message should be posted
+     * @param subscriptionEventData the data to be sent in the message
+     */
     suspend fun postMessage(
         webView: WebView,
         subscriptionEventData: SubscriptionEventData,
     )
 
+    /**
+     * The context for this instance.
+     * This can be used to differentiate between different messaging implementations.
+     * @return context string
+     */
     val context: String
 }