Makes copying layers clone external textures.

content/browser/renderer_host/render_widget_host_view_aura.cc

Index: content/browser/renderer_host/render_widget_host_view_aura.cc
diff --git a/content/browser/renderer_host/render_widget_host_view_aura.cc b/content/browser/renderer_host/render_widget_host_view_aura.cc
index c5d4edbdf2d0472a943e8a7875d0eff706326ed7..e41f17cc76d0c595fcf3311ae648e87622d0541a 100644
--- a/content/browser/renderer_host/render_widget_host_view_aura.cc
+++ b/content/browser/renderer_host/render_widget_host_view_aura.cc
@@ -1271,6 +1271,31 @@ bool RenderWidgetHostViewAura::HasHitTestMask() const {
 void RenderWidgetHostViewAura::GetHitTestMask(gfx::Path* mask) const {
 }
 
+scoped_refptr<ui::Texture> RenderWidgetHostViewAura::CopyTexture() {
+  if (!host_->is_accelerated_compositing_active())
+    return scoped_refptr<ui::Texture>();
+
+  ImageTransportFactory* factory = ImageTransportFactory::GetInstance();
+  GLHelper* gl_helper = factory->GetGLHelper();
+  if (!gl_helper)
+    return scoped_refptr<ui::Texture>();
+
+  std::map<uint64, scoped_refptr<ui::Texture> >::iterator it =
+      image_transport_clients_.find(current_surface_);
+  if (it == image_transport_clients_.end())
+    return scoped_refptr<ui::Texture>();
+
+  ui::Texture* container = it->second;
+  DCHECK(container);
+  WebKit::WebGLId texture_id =
+      gl_helper->CopyTexture(container->texture_id(), container->size());
+  if (!texture_id)
+    return scoped_refptr<ui::Texture>();
+
+  return scoped_refptr<ui::Texture>(
+      factory->CreateTransportClient(container->size(), texture_id));
+}
+
 ////////////////////////////////////////////////////////////////////////////////
 // RenderWidgetHostViewAura, ui::EventHandler implementation: