[Android] Suppress javascript dialogs from background tabs in custom tab

components/web_contents_delegate_android/web_contents_delegate_android.cc

Index: components/web_contents_delegate_android/web_contents_delegate_android.cc
diff --git a/components/web_contents_delegate_android/web_contents_delegate_android.cc b/components/web_contents_delegate_android/web_contents_delegate_android.cc
index 0f5d7db379b889ad56f86b33ef8a23a5b569364a..165dddc91455904df9b1c2018b859039d800018a 100644
--- a/components/web_contents_delegate_android/web_contents_delegate_android.cc
+++ b/components/web_contents_delegate_android/web_contents_delegate_android.cc
@@ -416,4 +416,17 @@ void WebContentsDelegateAndroid::RequestAppBannerFromDevTools(
     content::WebContents* web_contents) {
 }
 
+bool WebContentsDelegateAndroid::ShouldSuppressDialogs(
+    content::WebContents* web_contents) {
+  JNIEnv* env = AttachCurrentThread();
+  ScopedJavaLocalRef<jobject> obj = GetJavaDelegate(env);
+  if (obj.is_null())
+    return false;
+  ScopedJavaLocalRef<jobject> jsource_contents;
+  if (web_contents)
+    jsource_contents = web_contents->GetJavaWebContents();
+  return Java_WebContentsDelegateAndroid_shouldSuppressDialogs(
+        env, obj.obj(), jsource_contents.obj());
+}
+
 }  // namespace web_contents_delegate_android