Start of hardware overlay support in CC with Ubercompositor.

cc/resources/texture_mailbox.h

Index: cc/resources/texture_mailbox.h
diff --git a/cc/resources/texture_mailbox.h b/cc/resources/texture_mailbox.h
index 229f7a735148892d44106c22a67c656b4abe14b4..ecbfd2d7fd62be2fe68c524793d3d219959c9513 100644
--- a/cc/resources/texture_mailbox.h
+++ b/cc/resources/texture_mailbox.h
@@ -40,6 +40,9 @@ class CC_EXPORT TextureMailbox {
     mailbox_holder_.sync_point = sync_point;
   }
 
+  bool hw_backed() const { return hw_backed_; }

[piman, 2014/03/14 03:42:34]

nit: hw_backed is misleading. Regular textures are hardware-backed :)
How about allow_overlays or something like that?

[alexst (slow to review), 2014/03/14 19:54:22]

I went back and forth on the name and abbreviated my original one, 
backed_by_a_buffer_hardware_overlays_or_fast_2d_blitters_can_scan_from_directly_.
:) 

Let's go with allow_overlays, though the word overlay is a bit overused and
technically the hardware can decide to task a fast blitter or some such instead,
hence the generic name. But I suppose "overlay" is used in other places so this
will be consistent. 

+  void set_hw_backed(bool hw_backed) { hw_backed_ = hw_backed; }
+
   base::SharedMemory* shared_memory() const { return shared_memory_; }
   gfx::Size shared_memory_size() const { return shared_memory_size_; }
   size_t shared_memory_size_in_bytes() const;
@@ -48,6 +51,7 @@ class CC_EXPORT TextureMailbox {
   gpu::MailboxHolder mailbox_holder_;
   base::SharedMemory* shared_memory_;
   gfx::Size shared_memory_size_;
+  bool hw_backed_;
 };
 
 }  // namespace cc