Disable some compositing state asserts seen on Mac builds

Source/core/rendering/compositing/RenderLayerCompositor.cpp

Index: Source/core/rendering/compositing/RenderLayerCompositor.cpp
diff --git a/Source/core/rendering/compositing/RenderLayerCompositor.cpp b/Source/core/rendering/compositing/RenderLayerCompositor.cpp
index b38df7aca97b83ea9ec5ea1d6f24c0380180028d..9b6c45f52815da9a92a57be42cbb0b8ae5dd00b9 100644
--- a/Source/core/rendering/compositing/RenderLayerCompositor.cpp
+++ b/Source/core/rendering/compositing/RenderLayerCompositor.cpp
@@ -1302,6 +1302,9 @@ void RenderLayerCompositor::rootFixedBackgroundsChanged()
     if (!supportsFixedRootBackgroundCompositing())
         return;
 
+    // crbug.com/343132.
+    DisableCompositingQueryAsserts disabler;
+
     // To avoid having to make the fixed root background layer fixed positioned to
     // stay put, we position it in the layer tree as follows:
     //