Remove unnecessary null check

Author: CrisBarreiro

app/src/androidTest/java/com/duckduckgo/app/browser/BrowserWebViewClientTest.kt

@@ -1342,7 +1342,7 @@ class BrowserWebViewClientTest {
         }
 
         override fun register(
-            jsMessageCallback: JsMessageCallback?,
+            jsMessageCallback: JsMessageCallback,
             webView: WebView,
         ) {
             registered = true

content-scope-scripts/content-scope-scripts-impl/src/main/java/com/duckduckgo/contentscopescripts/impl/messaging/WebViewCompatWebCompatMessagingPlugin.kt

@@ -83,12 +83,11 @@ class WebViewCompatWebCompatMessagingPlugin @Inject constructor(
     }
 
     override fun register(
-        jsMessageCallback: JsMessageCallback?,
+        jsMessageCallback: JsMessageCallback,
         webView: WebView,
     ) {
         coroutineScope.launch {
             if (!webViewCompatContentScopeScripts.isEnabled()) return@launch
-            if (jsMessageCallback == null) throw Exception("Callback cannot be null")
 
             runCatching {
                 return@runCatching webViewCompatWrapper.addWebMessageListener(

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

@@ -20,7 +20,7 @@ import android.webkit.WebView
 
 interface WebMessagingPlugin {
     fun register(
-        jsMessageCallback: JsMessageCallback?,
+        jsMessageCallback: JsMessageCallback,
         webView: WebView,
     )
 

lint-rules/src/main/java/com/duckduckgo/lint/WebViewCompatApisUsageDetector.kt

@@ -34,8 +34,8 @@ class WebViewCompatApisUsageDetector : Detector(), SourceCodeScanner {
     companion object {
         val ISSUE_ADD_WEB_MESSAGE_LISTENER_USAGE: Issue = Issue.create(
             id = "AddWebMessageListenerUsage",
-            briefDescription = "Use safe WebMessageListener methods",
-            explanation = "Use `safeAddWebMessageListener` instead of `WebViewCompat.addWebMessageListener`",
+            briefDescription = "Use safe WebViewCompatWrapper methods",
+            explanation = "Use `WebViewCompatWrapper#addWebMessageListener` instead",
             category = Category.CORRECTNESS,
             severity = Severity.ERROR,
             implementation = Implementation(
@@ -46,8 +46,8 @@ class WebViewCompatApisUsageDetector : Detector(), SourceCodeScanner {
 
         val ISSUE_REMOVE_WEB_MESSAGE_LISTENER_USAGE: Issue = Issue.create(
             id = "RemoveWebMessageListenerUsage",
-            briefDescription = "Use safe WebMessageListener methods",
-            explanation = "Use `safeRemoveWebMessageListener` instead of `WebViewCompat.removeWebMessageListener`",
+            briefDescription = "Use safe WebViewCompatWrapper methods",
+            explanation = "Use `WebViewCompatWrapper#removeWebMessageListener` instead",
             category = Category.CORRECTNESS,
             severity = Severity.ERROR,
             implementation = Implementation(
@@ -59,7 +59,7 @@ class WebViewCompatApisUsageDetector : Detector(), SourceCodeScanner {
         val ISSUE_ADD_DOCUMENT_START_JAVASCRIPT_USAGE: Issue = Issue.create(
             id = "AddDocumentStartJavaScriptUsage",
             briefDescription = "Use safe WebViewCompatWrapper methods",
-            explanation = "Use `WebViewCompatWrapper#addDocumentStartJavaScript` instead of `WebViewCompat.addDocumentStartJavaScript`",
+            explanation = "Use `WebViewCompatWrapper#addDocumentStartJavaScript` instead",
             category = Category.CORRECTNESS,
             severity = Severity.ERROR,
             implementation = Implementation(