LibWeb: Don't assume backing store allocation succeeds on OOPWV resize

Backing store allocation can fail if the requested size is too small,
or too large. We should not crash when this happens.

Fixes #3986.

Libraries/LibWeb/OutOfProcessWebView.cpp

@@ -84,11 +84,22 @@ void OutOfProcessWebView::resize_event(GUI::ResizeEvent& event)
 {
     GUI::ScrollableWidget::resize_event(event);
 
-    m_front_bitmap = Gfx::Bitmap::create(Gfx::BitmapFormat::RGB32, available_size())->to_bitmap_backed_by_shared_buffer();
-    m_front_bitmap->shared_buffer()->share_with(client().server_pid());
+    m_front_bitmap = nullptr;
+    m_back_bitmap = nullptr;
+
+    // FIXME: Don't create a temporary bitmap just to convert it to one backed by a shared buffer.
+    if (auto helper = Gfx::Bitmap::create(Gfx::BitmapFormat::RGB32, available_size())) {
+        m_front_bitmap = helper->to_bitmap_backed_by_shared_buffer();
+        ASSERT(m_front_bitmap);
+        m_front_bitmap->shared_buffer()->share_with(client().server_pid());
+    }
 
-    m_back_bitmap = Gfx::Bitmap::create(Gfx::BitmapFormat::RGB32, available_size())->to_bitmap_backed_by_shared_buffer();
-    m_back_bitmap->shared_buffer()->share_with(client().server_pid());
+    // FIXME: Don't create a temporary bitmap just to convert it to one backed by a shared buffer.
+    if (auto helper = Gfx::Bitmap::create(Gfx::BitmapFormat::RGB32, available_size())) {
+        m_back_bitmap = helper->to_bitmap_backed_by_shared_buffer();
+        ASSERT(m_back_bitmap);
+        m_back_bitmap->shared_buffer()->share_with(client().server_pid());
+    }
 
     client().post_message(Messages::WebContentServer::SetViewportRect(Gfx::IntRect({ horizontal_scrollbar().value(), vertical_scrollbar().value() }, available_size())));
     request_repaint();