Add Assistant content URLs

This is surfaced in recents on Pixel devices for example.
Docs: https://developer.android.com/guide/app-actions/assistant-sharing

Co-authored-by: Jays2Kings <Jays2Kings@users.noreply.github.com>

app/src/main/java/eu/kanade/tachiyomi/ui/webview/WebViewActivity.kt

@@ -1,5 +1,6 @@
 package eu.kanade.tachiyomi.ui.webview
 
+import android.app.assist.AssistContent
 import android.content.Context
 import android.content.Intent
 import android.os.Bundle
@@ -25,6 +26,8 @@ class WebViewActivity : BaseActivity() {
     private val sourceManager: SourceManager by injectLazy()
     private val network: NetworkHelper by injectLazy()
 
+    private var assistUrl: String? = null
+
     init {
         registerSecureActivity(this)
     }
@@ -52,6 +55,7 @@ class WebViewActivity : BaseActivity() {
                 initialTitle = intent.extras?.getString(TITLE_KEY),
                 url = url,
                 headers = headers,
+                onUrlChange = { assistUrl = it },
                 onShare = this::shareWebpage,
                 onOpenInBrowser = this::openInBrowser,
                 onClearCookies = this::clearCookies,
@@ -59,6 +63,11 @@ class WebViewActivity : BaseActivity() {
         }
     }
 
+    override fun onProvideAssistContent(outContent: AssistContent) {
+        super.onProvideAssistContent(outContent)
+        assistUrl?.let { outContent.webUri = it.toUri() }
+    }
+
     override fun finish() {
         super.finish()
         overridePendingTransition(R.anim.shared_axis_x_pop_enter, R.anim.shared_axis_x_pop_exit)