DevTools: hide page overlay layers in LayerTreeAgent

Source/web/PageOverlay.cpp

Index: Source/web/PageOverlay.cpp
diff --git a/Source/web/PageOverlay.cpp b/Source/web/PageOverlay.cpp
index d9583aa8bbfdf124dee6cbb9b85091a11ea57c5f..2d4130f88b6a541e5f901d62897f41cce7264200 100644
--- a/Source/web/PageOverlay.cpp
+++ b/Source/web/PageOverlay.cpp
@@ -101,6 +101,8 @@ void PageOverlay::clear()
 
     if (m_layer) {
         m_layer->removeFromParent();
+        if (WebCore::Page* page = m_viewImpl->page())
+            page->inspectorController().didRemovePageOverlay(m_layer.get());
         m_layer = nullptr;
         m_layerClient = nullptr;
     }
@@ -115,6 +117,9 @@ void PageOverlay::update()
         m_layer = GraphicsLayer::create(m_viewImpl->graphicsLayerFactory(), m_layerClient.get());
         m_layer->setDrawsContent(true);
 
+        if (WebCore::Page* page = m_viewImpl->page())
+            page->inspectorController().willAddPageOverlay(m_layer.get());
+
         // Compositor hit-testing does not know how to deal with layers that may be
         // transparent to events (see http://crbug.com/269598). So require
         // scrolling and touches on this layer to go to the main thread.