cc: Move raster_source from Tile to PrioritizedTile

cc/resources/prioritized_tile.cc

Index: cc/resources/prioritized_tile.cc
diff --git a/cc/resources/prioritized_tile.cc b/cc/resources/prioritized_tile.cc
index 3a9f815fec4f58e5eddda61ac31339bb9678186c..18a3c3cba686eb228b7afa12fcc9590c9b688454 100644
--- a/cc/resources/prioritized_tile.cc
+++ b/cc/resources/prioritized_tile.cc
@@ -8,13 +8,18 @@
 
 namespace cc {
 
-PrioritizedTile::PrioritizedTile() : tile_(nullptr), is_occluded_(false) {
+PrioritizedTile::PrioritizedTile()
+    : tile_(nullptr), raster_source_(nullptr), is_occluded_(false) {
 }
 
 PrioritizedTile::PrioritizedTile(Tile* tile,
+                                 RasterSource* raster_source,
                                  const TilePriority priority,
                                  bool is_occluded)
-    : tile_(tile), priority_(priority), is_occluded_(is_occluded) {
+    : tile_(tile),
+      raster_source_(raster_source),
+      priority_(priority),
+      is_occluded_(is_occluded) {
 }
 
 PrioritizedTile::~PrioritizedTile() {