cc: Plumb more details about pixel refs to tile manager.

cc/tiles/image_decode_controller.cc

Index: cc/tiles/image_decode_controller.cc
diff --git a/cc/tiles/image_decode_controller.cc b/cc/tiles/image_decode_controller.cc
index bc1dfef7e920f356703f0a1a5bc0bb9e00d8cf63..9b3d1723b4f4effc542ebd8c4bd870f48defd7e5 100644
--- a/cc/tiles/image_decode_controller.cc
+++ b/cc/tiles/image_decode_controller.cc
@@ -60,14 +60,15 @@ ImageDecodeController::ImageDecodeController() {}
 ImageDecodeController::~ImageDecodeController() {}
 
 scoped_refptr<ImageDecodeTask> ImageDecodeController::GetTaskForPixelRef(
-    SkPixelRef* pixel_ref,
+    const skia::PositionPixelRef& pixel_ref,
     int layer_id,
     uint64_t prepare_tiles_id) {
-  uint32_t generation_id = pixel_ref->getGenerationID();
+  uint32_t generation_id = pixel_ref.pixel_ref->getGenerationID();
   scoped_refptr<ImageDecodeTask>& decode_task =
       image_decode_tasks_[layer_id][generation_id];
   if (!decode_task)
-    decode_task = CreateTaskForPixelRef(pixel_ref, layer_id, prepare_tiles_id);
+    decode_task =
+        CreateTaskForPixelRef(pixel_ref.pixel_ref, layer_id, prepare_tiles_id);
   return decode_task;
 }