cc: Drop locked decodes from checker image tracker on cache switch.

cc/tiles/tile_manager.cc

Index: cc/tiles/tile_manager.cc
diff --git a/cc/tiles/tile_manager.cc b/cc/tiles/tile_manager.cc
index e2d11552268c562607b140c1b0349d73670a49a1..7597883e12594fa6fd145ad0b2290a54977d8cee 100644
--- a/cc/tiles/tile_manager.cc
+++ b/cc/tiles/tile_manager.cc
@@ -403,6 +403,10 @@ void TileManager::FinishTasksAndCleanUp() {
   ready_to_draw_callback_weak_ptr_factory_.InvalidateWeakPtrs();
   raster_buffer_provider_ = nullptr;
 
+  // Ask the tracker to drop any locked decodes since we will be destroying the
+  // decode cache.
+  bool can_clear_decode_policy_tracking = false;
+  checker_image_tracker_.ClearTracker(can_clear_decode_policy_tracking);
   image_controller_.SetImageDecodeCache(nullptr);
   locked_image_tasks_.clear();
 }