cc: Clear checker-image tracking on navigation and visibility changes.

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 1c78b5353496048ab7f3c8f64d671522631592e8..5e75985ec7004dfe8b234568f4f7bc2805b95629 100644
--- a/cc/tiles/tile_manager.cc
+++ b/cc/tiles/tile_manager.cc
@@ -1395,6 +1395,10 @@ void TileManager::DidActivateSyncTree() {
   checker_image_tracker_.DidActivateSyncTree();
 }
 
+void TileManager::ClearCheckerImageTracking() {
+  checker_image_tracker_.ClearTracker();
+}
+
 void TileManager::NeedsInvalidationForCheckerImagedTiles() {
   client_->RequestImplSideInvalidation();
 }