Fix shutdown assertions in WebViewImpl

Source/web/WebViewImpl.cpp

Index: Source/web/WebViewImpl.cpp
diff --git a/Source/web/WebViewImpl.cpp b/Source/web/WebViewImpl.cpp
index 9f8c31ff244cd5c6fcd84ac10f547d188cc6ce3f..f55a4168b18f850fe190a364cbb30425e3aeccb4 100644
--- a/Source/web/WebViewImpl.cpp
+++ b/Source/web/WebViewImpl.cpp
@@ -3991,6 +3991,12 @@ void WebViewImpl::initializeLayerTreeView()
 
 void WebViewImpl::setIsAcceleratedCompositingActive(bool active)
 {
+    // In the middle of shutting down; don't try to spin back up a compositor.
+    // FIXME: compositing startup/shutdown should be refactored so that it
+    // turns on explicitly rather than lazily, which causes this awkwardness.
+    if (m_layerTreeViewClosed)
+        return;
+
     ASSERT(!active || m_layerTreeView);
     blink::Platform::current()->histogramEnumeration("GPU.setIsAcceleratedCompositingActive", active * 2 + m_isAcceleratedCompositingActive, 4);
 
@@ -4000,10 +4006,6 @@ void WebViewImpl::setIsAcceleratedCompositingActive(bool active)
     if (!m_client)
         return;
 
-    // In the middle of shutting down; don't try to spin back up a compositor.
-    if (m_layerTreeViewClosed)
-        return;
-
     if (!active) {
         m_isAcceleratedCompositingActive = false;
         if (!m_layerTreeViewCommitsDeferred) {