Add setVisibilityState API to WebFrameWidget

Source/web/WebFrameWidgetImpl.cpp

Index: Source/web/WebFrameWidgetImpl.cpp
diff --git a/Source/web/WebFrameWidgetImpl.cpp b/Source/web/WebFrameWidgetImpl.cpp
index df861ab42c9374debbbb3dc1fdb3eef2367b3741..750721cad70faded57c099858860ab151a1ba9a9 100644
--- a/Source/web/WebFrameWidgetImpl.cpp
+++ b/Source/web/WebFrameWidgetImpl.cpp
@@ -1014,4 +1014,19 @@ void WebFrameWidgetImpl::setRootGraphicsLayer(GraphicsLayer* layer)
     suppressInvalidations(false);
 }
 
+void WebFrameWidgetImpl::setVisibilityState(WebPageVisibilityState visibilityState, bool isInitialState)
+{
+    if (!m_page)
+        return;
+
+    // FIXME: This is not correct, since Show and Hide messages for a frame's Widget do not necessarily
+    // correspond to Page visibility, but is necessary until we properly sort out OOPIF visibility.
+    m_page->setVisibilityState(static_cast<PageVisibilityState>(visibilityState), isInitialState);
+
+    if (m_layerTreeView) {
+        bool visible = visibilityState == WebPageVisibilityStateVisible;
+        m_layerTreeView->setVisible(visible);
+    }
+}
+
 } // namespace blink