--- a/mobile/android/geckoview/src/main/java/org/mozilla/gecko/GeckoView.java
+++ b/mobile/android/geckoview/src/main/java/org/mozilla/gecko/GeckoView.java
@@ -109,17 +109,17 @@ public class GeckoView extends LayerView
     }
 
     @WrapForJNI(dispatchTo = "proxy")
     private static final class Window extends JNIObject {
         @WrapForJNI(skip = true)
         /* package */ Window() {}
 
         static native void open(Window instance, GeckoView view, Object compositor,
-                                String chromeURI, int width, int height);
+                                String chromeURI);
 
         @Override protected native void disposeNative();
         native void close();
         native void reattach(GeckoView view, Object compositor);
         native void loadUri(String uri, int flags);
     }
 
     // Object to hold onto our nsWindow connection when GeckoView gets destroyed.
@@ -220,27 +220,25 @@ public class GeckoView extends LayerView
         }
 
         // We have to always call super.onRestoreInstanceState because View keeps
         // track of these calls and throws an exception when we don't call it.
         super.onRestoreInstanceState(stateBinder.superState);
     }
 
     private void openWindow() {
-        final DisplayMetrics metrics = getContext().getResources().getDisplayMetrics();
-
         final String chromeURI = getGeckoInterface().getDefaultChromeURI();
 
         if (GeckoThread.isStateAtLeast(GeckoThread.State.PROFILE_READY)) {
             Window.open(window, this, getCompositor(),
-                        chromeURI, metrics.widthPixels, metrics.heightPixels);
+                        chromeURI);
         } else {
             GeckoThread.queueNativeCallUntil(GeckoThread.State.PROFILE_READY, Window.class,
                     "open", window, GeckoView.class, this, Object.class, getCompositor(),
-                    String.class, chromeURI, metrics.widthPixels, metrics.heightPixels);
+                    String.class, chromeURI);
         }
     }
 
     private void reattachWindow() {
         if (GeckoThread.isStateAtLeast(GeckoThread.State.PROFILE_READY)) {
             window.reattach(this, getCompositor());
         } else {
             GeckoThread.queueNativeCallUntil(GeckoThread.State.PROFILE_READY,

--- a/widget/android/GeneratedJNIWrappers.h
+++ b/widget/android/GeneratedJNIWrappers.h
@@ -3269,22 +3269,20 @@ public:
     struct Open_t {
         typedef Window Owner;
         typedef void ReturnType;
         typedef void SetterType;
         typedef mozilla::jni::Args<
                 Window::Param,
                 GeckoView::Param,
                 mozilla::jni::Object::Param,
-                mozilla::jni::String::Param,
-                int32_t,
-                int32_t> Args;
+                mozilla::jni::String::Param> Args;
         static constexpr char name[] = "open";
         static constexpr char signature[] =
-                "(Lorg/mozilla/gecko/GeckoView$Window;Lorg/mozilla/gecko/GeckoView;Ljava/lang/Object;Ljava/lang/String;II)V";
+                "(Lorg/mozilla/gecko/GeckoView$Window;Lorg/mozilla/gecko/GeckoView;Ljava/lang/Object;Ljava/lang/String;)V";
         static const bool isStatic = true;
         static const mozilla::jni::ExceptionMode exceptionMode =
                 mozilla::jni::ExceptionMode::ABORT;
         static const mozilla::jni::CallingThread callingThread =
                 mozilla::jni::CallingThread::ANY;
         static const mozilla::jni::DispatchTarget dispatchTarget =
                 mozilla::jni::DispatchTarget::PROXY;
     };

--- a/widget/android/nsWindow.cpp
+++ b/widget/android/nsWindow.cpp
@@ -340,18 +340,17 @@ public:
 private:
     nsCOMPtr<nsPIDOMWindowOuter> mDOMWindow;
 
 public:
     // Create and attach a window.
     static void Open(const jni::Class::LocalRef& aCls,
                      GeckoView::Window::Param aWindow,
                      GeckoView::Param aView, jni::Object::Param aCompositor,
-                     jni::String::Param aChromeURI,
-                     int32_t aWidth, int32_t aHeight);
+                     jni::String::Param aChromeURI);
 
     // Close and destroy the nsWindow.
     void Close();
 
     // Reattach this nsWindow to a new GeckoView.
     void Reattach(const GeckoView::Window::LocalRef& inst,
                   GeckoView::Param aView, jni::Object::Param aCompositor);
 
@@ -1315,18 +1314,17 @@ nsWindow::GeckoViewSupport::~GeckoViewSu
     }
 }
 
 /* static */ void
 nsWindow::GeckoViewSupport::Open(const jni::Class::LocalRef& aCls,
                                  GeckoView::Window::Param aWindow,
                                  GeckoView::Param aView,
                                  jni::Object::Param aCompositor,
-                                 jni::String::Param aChromeURI,
-                                 int32_t aWidth, int32_t aHeight)
+                                 jni::String::Param aChromeURI)
 {
     MOZ_ASSERT(NS_IsMainThread());
 
     PROFILER_LABEL("nsWindow", "GeckoViewSupport::Open",
                    js::ProfileEntry::Category::OTHER);
 
     nsCOMPtr<nsIWindowWatcher> ww = do_GetService(NS_WINDOWWATCHER_CONTRACTID);
     MOZ_RELEASE_ASSERT(ww);
@@ -1336,35 +1334,19 @@ nsWindow::GeckoViewSupport::Open(const j
         url = aChromeURI->ToCString();
     } else {
         url = Preferences::GetCString("toolkit.defaultChromeURI");
         if (!url) {
             url = NS_LITERAL_CSTRING("chrome://browser/content/browser.xul");
         }
     }
 
-    nsCOMPtr<nsISupportsArray> args
-            = do_CreateInstance(NS_SUPPORTSARRAY_CONTRACTID);
-    nsCOMPtr<nsISupportsPRInt32> widthArg
-            = do_CreateInstance(NS_SUPPORTS_PRINT32_CONTRACTID);
-    nsCOMPtr<nsISupportsPRInt32> heightArg
-            = do_CreateInstance(NS_SUPPORTS_PRINT32_CONTRACTID);
-
-    // Arguments are optional so it's okay if this fails.
-    if (args && widthArg && heightArg &&
-            NS_SUCCEEDED(widthArg->SetData(aWidth)) &&
-            NS_SUCCEEDED(heightArg->SetData(aHeight)))
-    {
-        args->AppendElement(widthArg);
-        args->AppendElement(heightArg);
-    }
-
     nsCOMPtr<mozIDOMWindowProxy> domWindow;
     ww->OpenWindow(nullptr, url, nullptr, "chrome,dialog=0,resizable",
-                   args, getter_AddRefs(domWindow));
+                   nullptr, getter_AddRefs(domWindow));
     MOZ_RELEASE_ASSERT(domWindow);
 
     nsCOMPtr<nsPIDOMWindowOuter> pdomWindow =
             nsPIDOMWindowOuter::From(domWindow);
     nsCOMPtr<nsIWidget> widget = WidgetUtils::DOMWindowToWidget(pdomWindow);
     MOZ_ASSERT(widget);
 
     const auto window = static_cast<nsWindow*>(widget.get());