diff --git a/mobile/android/components/geckoview/GeckoViewPrompt.js b/mobile/android/components/geckoview/GeckoViewPrompt.js
index ab4371518d83..4277696fb06e 100644
--- a/mobile/android/components/geckoview/GeckoViewPrompt.js
+++ b/mobile/android/components/geckoview/GeckoViewPrompt.js
@@ -30,6 +30,8 @@ function PromptFactory() {
   this.wrappedJSObject = this;
 }
 
+const { debug, warn } = GeckoViewUtils.initLogging("GeckoViewPrompt"); // eslint-disable-line no-unused-vars
+
 PromptFactory.prototype = {
   classID: Components.ID("{076ac188-23c1-4390-aa08-7ef1f78ca5d9}"),
 
@@ -332,7 +334,7 @@ PromptFactory.prototype = {
   _handlePopupBlocked: function(aEvent) {
     const dwi = aEvent.requestingWindow;
     const popupWindowURISpec = aEvent.popupWindowURI
-      ? aEvent.popupWindowURI.spec
+      ? aEvent.popupWindowURI.displaySpec
       : "about:blank";
 
     let prompt = new PromptDelegate(aEvent.requestingWindow);
@@ -341,8 +343,8 @@ PromptFactory.prototype = {
         type: "popup",
         targetUri: popupWindowURISpec,
       },
-      allowed => {
-        if (allowed && dwi) {
+      ({ response }) => {
+        if (response && dwi) {
           dwi.open(
             popupWindowURISpec,
             aEvent.popupWindowName,
diff --git a/mobile/android/geckoview/src/androidTest/java/org/mozilla/geckoview/test/BaseSessionTest.kt b/mobile/android/geckoview/src/androidTest/java/org/mozilla/geckoview/test/BaseSessionTest.kt
index 33b1e92f1f68..4c2f63da1033 100644
--- a/mobile/android/geckoview/src/androidTest/java/org/mozilla/geckoview/test/BaseSessionTest.kt
+++ b/mobile/android/geckoview/src/androidTest/java/org/mozilla/geckoview/test/BaseSessionTest.kt
@@ -173,6 +173,8 @@ open class BaseSessionTest(noErrorCollector: Boolean = false) {
     fun GeckoSession.waitForJS(js: String): Any? =
             sessionRule.waitForJS(this, js)
 
+    fun GeckoSession.waitForRoundTrip() = sessionRule.waitForRoundTrip(this)
+
     @Suppress("UNCHECKED_CAST")
     fun Any?.asJsonArray(): JSONArray = this as JSONArray
 
diff --git a/mobile/android/geckoview/src/androidTest/java/org/mozilla/geckoview/test/PromptDelegateTest.kt b/mobile/android/geckoview/src/androidTest/java/org/mozilla/geckoview/test/PromptDelegateTest.kt
index 794607b54382..96595fb83318 100644
--- a/mobile/android/geckoview/src/androidTest/java/org/mozilla/geckoview/test/PromptDelegateTest.kt
+++ b/mobile/android/geckoview/src/androidTest/java/org/mozilla/geckoview/test/PromptDelegateTest.kt
@@ -20,24 +20,6 @@ import org.junit.runner.RunWith
 @RunWith(AndroidJUnit4::class)
 @MediumTest
 class PromptDelegateTest : BaseSessionTest() {
-    @Ignore("disable test for frequently failing Bug 1535423")
-    @Test fun popupTest() {
-        // Ensure popup blocking is enabled for this test.
-        sessionRule.setPrefsUntilTestEnd(mapOf("dom.disable_open_during_load" to true))
-        sessionRule.session.loadTestPath(POPUP_HTML_PATH)
-
-        sessionRule.waitUntilCalled(object : Callbacks.PromptDelegate {
-            @AssertCalled(count = 1)
-            override fun onPopupPrompt(session: GeckoSession, prompt: PromptDelegate.PopupPrompt)
-                    : GeckoResult<PromptDelegate.PromptResponse>? {
-                assertThat("Session should not be null", session, notNullValue())
-                assertThat("URL should not be null", prompt.targetUri, notNullValue())
-                assertThat("URL should match", prompt.targetUri, endsWith(HELLO_HTML_PATH))
-                return null
-            }
-        })
-    }
-
     @Test fun popupTestAllow() {
         // Ensure popup blocking is enabled for this test.
         sessionRule.setPrefsUntilTestEnd(mapOf("dom.disable_open_during_load" to true))
@@ -60,6 +42,13 @@ class PromptDelegateTest : BaseSessionTest() {
                 assertThat("URL should match", request.uri, endsWith(forEachCall(POPUP_HTML_PATH, HELLO_HTML_PATH)))
                 return null
             }
+
+            @AssertCalled(count = 1)
+            override fun onNewSession(session: GeckoSession, uri: String): GeckoResult<GeckoSession>? {
+                assertThat("URL should not be null", uri, notNullValue())
+                assertThat("URL should match", uri, endsWith(HELLO_HTML_PATH))
+                return null
+            }
         })
 
         sessionRule.session.loadTestPath(POPUP_HTML_PATH)
@@ -70,7 +59,7 @@ class PromptDelegateTest : BaseSessionTest() {
         // Ensure popup blocking is enabled for this test.
         sessionRule.setPrefsUntilTestEnd(mapOf("dom.disable_open_during_load" to true))
 
-        sessionRule.delegateDuringNextWait(object : Callbacks.PromptDelegate, Callbacks.NavigationDelegate {
+        sessionRule.delegateUntilTestEnd(object : Callbacks.PromptDelegate, Callbacks.NavigationDelegate {
             @AssertCalled(count = 1)
             override fun onPopupPrompt(session: GeckoSession, prompt: PromptDelegate.PopupPrompt)
                     : GeckoResult<PromptDelegate.PromptResponse>? {
@@ -96,7 +85,8 @@ class PromptDelegateTest : BaseSessionTest() {
         })
 
         sessionRule.session.loadTestPath(POPUP_HTML_PATH)
-        sessionRule.session.waitForPageStop()
+        sessionRule.waitForPageStop()
+        sessionRule.session.waitForRoundTrip()
     }
 
     @Ignore // TODO: Reenable when 1501574 is fixed.
diff --git a/mobile/android/geckoview/src/androidTest/java/org/mozilla/geckoview/test/rule/GeckoSessionTestRule.java b/mobile/android/geckoview/src/androidTest/java/org/mozilla/geckoview/test/rule/GeckoSessionTestRule.java
index 12144ad12a22..bce204f4e4a1 100644
--- a/mobile/android/geckoview/src/androidTest/java/org/mozilla/geckoview/test/rule/GeckoSessionTestRule.java
+++ b/mobile/android/geckoview/src/androidTest/java/org/mozilla/geckoview/test/rule/GeckoSessionTestRule.java
@@ -1321,6 +1321,13 @@ public class GeckoSessionTestRule implements TestRule {
         };
     }
 
+    /**
+     * This simply sends an empty message to the web content and waits for a reply.
+     */
+    public void waitForRoundTrip(final GeckoSession session) {
+        waitForJS(session, "true");
+    }
+
     /**
      * Wait until a page load has finished on any session. A session must have started a
      * page load since the last wait, or this method will wait indefinitely.