Remove WebCompositorSupport::initialize/shutdown dependency from webkit_support::CreateLayerTreeView

webkit/support/webkit_support.h

Index: webkit/support/webkit_support.h
diff --git a/webkit/support/webkit_support.h b/webkit/support/webkit_support.h
index d8997905c4b77d49cbc994a775e939b2d33b00d0..600500448519109b34f95c5c0a30eb9a8704d817 100644
--- a/webkit/support/webkit_support.h
+++ b/webkit/support/webkit_support.h
@@ -133,6 +133,12 @@ WebKit::WebGraphicsContext3D* CreateGraphicsContext3D(
     const WebKit::WebGraphicsContext3D::Attributes& attributes,
     WebKit::WebView* web_view);
 
+enum LayerTreeViewType {
+  FAKE_CONTEXT,
+  SOFTWARE_CONTEXT,
+  MESA_CONTEXT
+};
+
 class DRTLayerTreeViewClient {
  public:
   virtual ~DRTLayerTreeViewClient() { }
@@ -140,6 +146,12 @@ class DRTLayerTreeViewClient {
   virtual void ScheduleComposite() = 0;
 };
 
+WebKit::WebLayerTreeView* CreateLayerTreeView(
+    LayerTreeViewType type,
+    DRTLayerTreeViewClient* client,
+    WebKit::WebThread* thread);
+
+// DEPRECATED. TODO(jamesr): Remove these two after fixing WebKit-side callers.
 WebKit::WebLayerTreeView* CreateLayerTreeViewSoftware(
     DRTLayerTreeViewClient* client);
 WebKit::WebLayerTreeView* CreateLayerTreeView3d(