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..63438fab2a7de6bb3d768929f6d1d7d5e3fa7c11 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 +1271,28 @@ bool RenderWidgetHostViewAura::HasHitTestMask() const {
 void RenderWidgetHostViewAura::GetHitTestMask(gfx::Path* mask) const {
 }
 
+scoped_refptr<ui::Texture> RenderWidgetHostViewAura::CopyTexture() {
+  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())

[piman, 2012/09/13 00:19:10]

Maybe also check host_->is_accelerated_compositing_active() otherwise during
some transitional states I believe current_surface_ may be set (and you'll find
a client, but it will be stale).

+    return scoped_refptr<ui::Texture>();
+
+  ui::Texture* container = it->second;
+  DCHECK(container);
+  gfx::Size size_in_pixels(ConvertSizeToPixel(this, window_->bounds().size()));

[piman, 2012/09/13 00:19:10]

How about texture->size() ? That way you're guaranteed to copy the exact size of
the texture, regardless of transitional states (e.g. we're waiting for the
renderer to produce a texture of the correct size), or the
layer->scale_content() settings.

+  WebKit::WebGLId surface_handle =

[piman, 2012/09/13 00:19:10]

nit: I'd name this texture_id or something. It's really not linked to a notion
of a surface any more.

+      gl_helper->CopyTexture(container->texture_id(), size_in_pixels);
+  if (!surface_handle)
+    return scoped_refptr<ui::Texture>();
+  return scoped_refptr<ui::Texture>(
+      factory->CreateTransportClient(size_in_pixels, surface_handle));
+}
+
 ////////////////////////////////////////////////////////////////////////////////
 // RenderWidgetHostViewAura, ui::EventHandler implementation: