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..45177721b6432802dfe9ab1e22194d8c42fb3f1b 100644
--- a/Source/web/WebFrameWidgetImpl.cpp
+++ b/Source/web/WebFrameWidgetImpl.cpp
@@ -1014,4 +1014,18 @@ void WebFrameWidgetImpl::setRootGraphicsLayer(GraphicsLayer* layer)
     suppressInvalidations(false);
 }
 
+void WebFrameWidgetImpl::setVisibilityState(WebPageVisibilityState visibilityState, bool isInitialState)
+{
+    if (!m_page)
+        return;
+
+    ASSERT(visibilityState == WebPageVisibilityStateVisible || visibilityState == WebPageVisibilityStateHidden || visibilityState == WebPageVisibilityStatePrerender);

[dcheng, 2015/02/26 17:42:08]

I guess the original implementation has this, but this assert seems unnecessary.
Do we usually assert on things like this? This assert just contains all the
valid enum values, which is what I would have expected to begin with =)

[kenrb, 2015/02/26 18:08:52]

I think it is just a guard. Looks like brettw originally suggested it, in a
review 4 years ago, and was intended to substitute for a switch.

+    m_page->setVisibilityState(static_cast<PageVisibilityState>(static_cast<int>(visibilityState)), isInitialState);

[dcheng, 2015/02/26 17:42:08]

Can we just static_cast<> directly to PageVisibilityState here?

[kenrb, 2015/02/26 18:08:52]

Apparently we can. Looks like on oversight in the original code.

+
+    if (m_layerTreeView) {
+        bool visible = visibilityState == WebPageVisibilityStateVisible;
+        m_layerTreeView->setVisible(visible);
+    }
+}
+
 } // namespace blink