Add PictureLayerTiling pointer to Tile

cc/tiles/picture_layer_tiling_unittest.cc

 // Copyright 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "cc/tiles/picture_layer_tiling.h"
 
 #include <stddef.h>
 
 #include <limits>
 #include <set>
@@ skipping 1044 matching lines @@
 
 TEST_F(PictureLayerTilingIteratorTest, TightCover2) {
   // In this test, the left edge of tile #38 almost (but failed to) covered
   // grid line x = 9653. Tile #37 needs to reach hard to x = 9654 to make up
   // for this.
   Initialize(gfx::Size(256, 256), 1.f, gfx::Size(10000, 1));
   float dest_scale = 16778088.f / 16777216.f;  // 0b1.00000000 00000011 01101000
   VerifyTilesExactlyCoverRect(dest_scale, gfx::Rect(10001, 2));
 }
 
+TEST_F(PictureLayerTilingIteratorTest, TilesStoreTilings) {
+  gfx::Size bounds(200, 200);
+  Initialize(gfx::Size(100, 100), 1.f, bounds);
+  SetLiveRectAndVerifyTiles(gfx::Rect(bounds));
+
+  // Get all tiles and ensure they are associated with |tiling_|.
+  std::vector<Tile*> tiles = tiling_->AllTilesForTesting();
+  EXPECT_TRUE(tiles.size());
+  for (const auto* tile : tiles) {
+    EXPECT_EQ(tile->tiling(), tiling_.get());
+  }
+
+  // Create an active tiling, transfer tiles to that tiling, and ensure that
+  // the tiles have their tiling updated.
+  scoped_refptr<FakeRasterSource> raster_source =
+      FakeRasterSource::CreateFilled(bounds);
+  auto active_tiling = TestablePictureLayerTiling::Create(
+      ACTIVE_TREE, 1.f, raster_source, &client_, LayerTreeSettings());
+  active_tiling->set_resolution(HIGH_RESOLUTION);
+
+  active_tiling->TakeTilesAndPropertiesFrom(tiling_.get(),
+                                            Region(gfx::Rect(bounds)));
+  for (const auto* tile : tiles) {
+    EXPECT_EQ(tile->tiling(), active_tiling.get());
+  }
+}
+
 }  // namespace
 }  // namespace cc