Implement the logic to kick off image decoding jobs for TileManager

cc/picture_pile_impl.h

Index: cc/picture_pile_impl.h
diff --git a/cc/picture_pile_impl.h b/cc/picture_pile_impl.h
index 5e9d65d4026cd8f28680e834016df798e61be0a3..3b75891ba04288615d745ca3bfce05feb5ecc13c 100644
--- a/cc/picture_pile_impl.h
+++ b/cc/picture_pile_impl.h
@@ -5,6 +5,7 @@
 #ifndef CC_PICTURE_PILE_IMPL_H_
 #define CC_PICTURE_PILE_IMPL_H_
 
+#include <list>
 #include <map>
 
 #include "base/basictypes.h"
@@ -38,6 +39,8 @@ public:
       float contents_scale,
       RenderingStats* stats);
 
+  void GatherPixelRefs(const gfx::Rect&, std::list<skia::LazyPixelRef*>&);
+
 private:
   friend class PicturePile;