PageOverlays: Remove PageOverlayList

Source/web/InspectorOverlayImpl.cpp

Index: Source/web/InspectorOverlayImpl.cpp
diff --git a/Source/web/InspectorOverlayImpl.cpp b/Source/web/InspectorOverlayImpl.cpp
index 3b54b28a091778109e4b3becf3416087e4fff98a..0c9e9c3d8af7fd4dbafa3f25ad77be75ef37d2a6 100644
--- a/Source/web/InspectorOverlayImpl.cpp
+++ b/Source/web/InspectorOverlayImpl.cpp
@@ -54,11 +54,6 @@
 #include "web/WebViewImpl.h"
 #include <v8.h>
 
-namespace OverlayZOrders {
-// Use 99 as a big z-order number so that highlight is above other overlays.
-static const int highlight = 99;
-}
-
 namespace blink {
 
 namespace {
@@ -178,7 +173,7 @@ void InspectorOverlayImpl::paintPageOverlay(WebGraphicsContext* context, const W
 
 void InspectorOverlayImpl::invalidate()
 {
-    m_webViewImpl->addPageOverlay(this, OverlayZOrders::highlight);
+    m_webViewImpl->addPageOverlay(this);
 }
 
 void InspectorOverlayImpl::layout()