cc: Remove tile sharing from tilings.

cc/resources/tile_manager.cc

Index: cc/resources/tile_manager.cc
diff --git a/cc/resources/tile_manager.cc b/cc/resources/tile_manager.cc
index 1e3c132ab646e4078f458dcc236dfe711f34723b..1e763a07d3534ba355917f31868780a23764525e 100644
--- a/cc/resources/tile_manager.cc
+++ b/cc/resources/tile_manager.cc
@@ -797,6 +797,15 @@ bool TileManager::AreRequiredTilesReadyToDraw(
     if (!raster_priority_queue->Top()->IsReadyToDraw())
       return false;
   }
+
+#if DCHECK_IS_ON()
+  scoped_ptr<RasterTilePriorityQueue> all_queue(
+      client_->BuildRasterQueue(global_state_.tree_priority, type));
+  for (; !all_queue->IsEmpty(); all_queue->Pop()) {
+    auto* tile = all_queue->Top();
+    DCHECK_IMPLIES(tile->required_for_activation(), tile->IsReadyToDraw());
+  }
+#endif
   return true;
 }
 bool TileManager::IsReadyToActivate() const {