[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 5160bf6c34fbd23f33c5f943d2a8fa9b325b5ba3..dac14057a2ed506e9fb059dfaf420076174123cb 100644
--- a/ui/aura/window.cc
+++ b/ui/aura/window.cc
@@ -34,6 +34,15 @@
 
 namespace aura {
 
+namespace {
+
+void MailboxReleaseCallback(scoped_ptr<base::SharedMemory> shared_memory,
+                            unsigned sync_point, bool lost_resource) {
+  // NOTE: shared_memory will get released when we go out of scope.
+}
+
+}  // namespace
+
 Window::Window(WindowDelegate* delegate)
     : type_(client::WINDOW_TYPE_UNKNOWN),
       owned_by_parent_(true),
@@ -145,6 +154,9 @@ ui::Layer* Window::RecreateLayer() {
     return NULL;
 
   old_layer->set_delegate(NULL);
+  float mailbox_scale_factor;
+  cc::TextureMailbox old_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());
@@ -158,8 +170,26 @@ ui::Layer* Window::RecreateLayer() {
   // Move the original texture to the new layer if the old layer has a
   // texture and we could copy it into the old layer,
   // crbug.com/175211.
-  if (delegate_ && old_texture)
+  if (delegate_ && old_texture) {
     layer_->SetExternalTexture(old_texture);
+  } else if (old_mailbox.IsSharedMemory()) {
+    base::SharedMemory* old_buffer = old_mailbox.shared_memory();
+    const size_t size = old_mailbox.shared_memory_size_in_bytes();
+
+    scoped_ptr<base::SharedMemory> new_buffer(new base::SharedMemory);
+    new_buffer->CreateAndMapAnonymous(size);
+
+    if (old_buffer->memory() && new_buffer->memory()) {
+      memcpy(new_buffer->memory(), old_buffer->memory(), size);
+      base::SharedMemory* new_buffer_raw_ptr = new_buffer.get();
+      cc::TextureMailbox::ReleaseCallback callback =
+          base::Bind(MailboxReleaseCallback, Passed(&new_buffer));
+      cc::TextureMailbox new_mailbox(new_buffer_raw_ptr,
+                                     old_mailbox.shared_memory_size(),
+                                     callback);
+      layer_->SetTextureMailbox(new_mailbox, mailbox_scale_factor);
+    }
+  }
 
   UpdateLayerName(name_);
   layer_->SetFillsBoundsOpaquely(!transparent_);
@@ -313,10 +343,6 @@ 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);