[Aura] Added Support for rendering software compositor frames as cc::TextureLayers.

ui/aura/window.cc

Index: ui/aura/window.cc
diff --git a/ui/aura/window.cc b/ui/aura/window.cc
index c1f7487309be081a743a3e1696c245d952f05976..bbb1ccd8901255934f59c488cd3b76801ed16ff9 100644
--- a/ui/aura/window.cc
+++ b/ui/aura/window.cc
@@ -145,6 +145,9 @@ ui::Layer* Window::RecreateLayer() {
     return NULL;
 
   old_layer->set_delegate(NULL);
+  float mailbox_scale_factor;
+  cc::TextureMailbox mailbox =
+      old_layer->GetTextureMailbox(&mailbox_scale_factor);
   scoped_refptr<ui::Texture> old_texture = old_layer->external_texture();
   if (delegate_ && old_texture)
     old_layer->SetExternalTexture(delegate_->CopyTexture());
@@ -160,6 +163,8 @@ ui::Layer* Window::RecreateLayer() {
   // crbug.com/175211.
   if (delegate_ && old_texture)
     layer_->SetExternalTexture(old_texture);
+  else if (mailbox.IsValid())
+    layer_->SetTextureMailbox(mailbox, mailbox_scale_factor);
 
   UpdateLayerName(name_);
   layer_->SetFillsBoundsOpaquely(!transparent_);
@@ -313,10 +318,6 @@ void Window::SchedulePaintInRect(const gfx::Rect& rect) {
   }
 }
 
-void Window::SetExternalTexture(ui::Texture* texture) {
-  layer_->SetExternalTexture(texture);
-}
-
 void Window::SetDefaultParentByRootWindow(RootWindow* root_window,
                                           const gfx::Rect& bounds_in_screen) {
   DCHECK(root_window);