cc: Move prepaint region calculations to the tiling set.

cc/tiles/picture_layer_tiling_set_unittest.cc

Index: cc/tiles/picture_layer_tiling_set_unittest.cc
diff --git a/cc/tiles/picture_layer_tiling_set_unittest.cc b/cc/tiles/picture_layer_tiling_set_unittest.cc
index ceb40dcae7a4b97bb23140086d93254d9cadb205..019e5abda6351b0c240889f9e9910887265dd38b 100644
--- a/cc/tiles/picture_layer_tiling_set_unittest.cc
+++ b/cc/tiles/picture_layer_tiling_set_unittest.cc
@@ -21,19 +21,43 @@
 namespace cc {
 namespace {
 
-std::unique_ptr<PictureLayerTilingSet> CreateTilingSet(
+class TestablePictureLayerTilingSet : public PictureLayerTilingSet {
+ public:
+  TestablePictureLayerTilingSet(
+      WhichTree tree,
+      PictureLayerTilingClient* client,
+      int tiling_interest_area_padding,
+      float skewport_target_time_in_seconds,
+      int skewport_extrapolation_limit_in_screen_pixels)
+      : PictureLayerTilingSet(tree,
+                              client,
+                              tiling_interest_area_padding,
+                              skewport_target_time_in_seconds,
+                              skewport_extrapolation_limit_in_screen_pixels) {}
+
+  using PictureLayerTilingSet::ComputeSkewport;
+  using PictureLayerTilingSet::ComputeSoonBorderRect;
+  using PictureLayerTilingSet::TilingsNeedUpdate;
+};
+
+std::unique_ptr<TestablePictureLayerTilingSet> CreateTilingSetWithSettings(
+    PictureLayerTilingClient* client,
+    const LayerTreeSettings& settings) {
+  return base::WrapUnique(new TestablePictureLayerTilingSet(
+      ACTIVE_TREE, client, settings.tiling_interest_area_padding,
+      settings.skewport_target_time_in_seconds,
+      settings.skewport_extrapolation_limit_in_screen_pixels));
+}
+
+std::unique_ptr<TestablePictureLayerTilingSet> CreateTilingSet(
     PictureLayerTilingClient* client) {
-  LayerTreeSettings defaults;
-  return PictureLayerTilingSet::Create(
-      ACTIVE_TREE, client, defaults.tiling_interest_area_padding,
-      defaults.skewport_target_time_in_seconds,
-      defaults.skewport_extrapolation_limit_in_content_pixels);
+  return CreateTilingSetWithSettings(client, LayerTreeSettings());
 }
 
 TEST(PictureLayerTilingSetTest, NoResources) {
   FakePictureLayerTilingClient client;
   gfx::Size layer_bounds(1000, 800);
-  std::unique_ptr<PictureLayerTilingSet> set = CreateTilingSet(&client);
+  std::unique_ptr<TestablePictureLayerTilingSet> set = CreateTilingSet(&client);
   client.SetTileSize(gfx::Size(256, 256));
 
   scoped_refptr<FakeRasterSource> raster_source =
@@ -77,7 +101,7 @@ TEST(PictureLayerTilingSetTest, TilingRange) {
   scoped_refptr<FakeRasterSource> raster_source =
       FakeRasterSource::CreateFilled(layer_bounds);
 
-  std::unique_ptr<PictureLayerTilingSet> set = CreateTilingSet(&client);
+  std::unique_ptr<TestablePictureLayerTilingSet> set = CreateTilingSet(&client);
   set->AddTiling(2.0, raster_source);
   high_res_tiling = set->AddTiling(1.0, raster_source);
   high_res_tiling->set_resolution(HIGH_RESOLUTION);
@@ -109,7 +133,7 @@ TEST(PictureLayerTilingSetTest, TilingRange) {
   EXPECT_EQ(4u, lower_than_low_res_range.start);
   EXPECT_EQ(5u, lower_than_low_res_range.end);
 
-  std::unique_ptr<PictureLayerTilingSet> set_without_low_res =
+  std::unique_ptr<TestablePictureLayerTilingSet> set_without_low_res =
       CreateTilingSet(&client);
   set_without_low_res->AddTiling(2.0, raster_source);
   high_res_tiling = set_without_low_res->AddTiling(1.0, raster_source);
@@ -140,8 +164,8 @@ TEST(PictureLayerTilingSetTest, TilingRange) {
       PictureLayerTilingSet::LOWER_THAN_LOW_RES);
   EXPECT_EQ(0u, lower_than_low_res_range.end - lower_than_low_res_range.start);
 
-  std::unique_ptr<PictureLayerTilingSet> set_with_only_high_and_low_res =
-      CreateTilingSet(&client);
+  std::unique_ptr<TestablePictureLayerTilingSet>
+      set_with_only_high_and_low_res = CreateTilingSet(&client);
   high_res_tiling =
       set_with_only_high_and_low_res->AddTiling(1.0, raster_source);
   high_res_tiling->set_resolution(HIGH_RESOLUTION);
@@ -174,7 +198,7 @@ TEST(PictureLayerTilingSetTest, TilingRange) {
       PictureLayerTilingSet::LOWER_THAN_LOW_RES);
   EXPECT_EQ(0u, lower_than_low_res_range.end - lower_than_low_res_range.start);
 
-  std::unique_ptr<PictureLayerTilingSet> set_with_only_high_res =
+  std::unique_ptr<TestablePictureLayerTilingSet> set_with_only_high_res =
       CreateTilingSet(&client);
   high_res_tiling = set_with_only_high_res->AddTiling(1.0, raster_source);
   high_res_tiling->set_resolution(HIGH_RESOLUTION);
@@ -224,7 +248,8 @@ class PictureLayerTilingSetTestWithResources : public testing::Test {
     FakePictureLayerTilingClient client(resource_provider.get());
     client.SetTileSize(gfx::Size(256, 256));
     gfx::Size layer_bounds(1000, 800);
-    std::unique_ptr<PictureLayerTilingSet> set = CreateTilingSet(&client);
+    std::unique_ptr<TestablePictureLayerTilingSet> set =
+        CreateTilingSet(&client);
     scoped_refptr<FakeRasterSource> raster_source =
         FakeRasterSource::CreateFilled(layer_bounds);
 
@@ -460,5 +485,504 @@ TEST(PictureLayerTilingSetTest, MaxContentScale) {
   EXPECT_EQ(2u, active_set->num_tilings());
 }
 
+TEST(PictureLayerTilingSetTest, SkewportLimits) {
+  FakePictureLayerTilingClient client;
+
+  gfx::Rect viewport(0, 0, 100, 100);
+  gfx::Size layer_bounds(200, 200);
+
+  client.SetTileSize(gfx::Size(100, 100));
+  LayerTreeSettings settings;
+  settings.skewport_extrapolation_limit_in_screen_pixels = 75;
+  settings.tiling_interest_area_padding = 1000000;
+
+  scoped_refptr<FakeRasterSource> raster_source =
+      FakeRasterSource::CreateFilled(layer_bounds);
+  std::unique_ptr<TestablePictureLayerTilingSet> tiling_set =
+      CreateTilingSetWithSettings(&client, settings);
+
+  EXPECT_FALSE(tiling_set->TilingsNeedUpdate(viewport, 1.0));
+  tiling_set->AddTiling(1.f, raster_source);
+  EXPECT_TRUE(tiling_set->TilingsNeedUpdate(viewport, 1.0));
+
+  tiling_set->UpdateTilePriorities(viewport, 1.f, 1.0, Occlusion(), true);
+
+  // Move viewport down 50 pixels in 0.5 seconds.
+  gfx::Rect down_skewport =
+      tiling_set->ComputeSkewport(gfx::Rect(0, 50, 100, 100), 1.5, 1.f);
+
+  EXPECT_EQ(0, down_skewport.x());
+  EXPECT_EQ(50, down_skewport.y());
+  EXPECT_EQ(100, down_skewport.width());
+  EXPECT_EQ(175, down_skewport.height());
+  EXPECT_TRUE(down_skewport.Contains(gfx::Rect(0, 50, 100, 100)));
+
+  // Move viewport down 50 and right 10 pixels.
+  gfx::Rect down_right_skewport =
+      tiling_set->ComputeSkewport(gfx::Rect(10, 50, 100, 100), 1.5, 1.f);
+
+  EXPECT_EQ(10, down_right_skewport.x());
+  EXPECT_EQ(50, down_right_skewport.y());
+  EXPECT_EQ(120, down_right_skewport.width());
+  EXPECT_EQ(175, down_right_skewport.height());
+  EXPECT_TRUE(down_right_skewport.Contains(gfx::Rect(10, 50, 100, 100)));
+
+  // Move viewport left.
+  gfx::Rect left_skewport =
+      tiling_set->ComputeSkewport(gfx::Rect(-50, 0, 100, 100), 1.5, 1.f);
+
+  EXPECT_EQ(-125, left_skewport.x());
+  EXPECT_EQ(0, left_skewport.y());
+  EXPECT_EQ(175, left_skewport.width());
+  EXPECT_EQ(100, left_skewport.height());
+  EXPECT_TRUE(left_skewport.Contains(gfx::Rect(-50, 0, 100, 100)));
+
+  // Expand viewport.
+  gfx::Rect expand_skewport =
+      tiling_set->ComputeSkewport(gfx::Rect(-50, -50, 200, 200), 1.5, 1.f);
+
+  // x and y moved by -75 (-50 - 75 = -125).
+  // right side and bottom side moved by 75 [(350 - 125) - (200 - 50) = 75].
+  EXPECT_EQ(-125, expand_skewport.x());
+  EXPECT_EQ(-125, expand_skewport.y());
+  EXPECT_EQ(350, expand_skewport.width());
+  EXPECT_EQ(350, expand_skewport.height());
+  EXPECT_TRUE(expand_skewport.Contains(gfx::Rect(-50, -50, 200, 200)));
+
+  // Expand the viewport past the limit in all directions.
+  gfx::Rect big_expand_skewport =
+      tiling_set->ComputeSkewport(gfx::Rect(-500, -500, 1500, 1500), 1.5, 1.f);
+
+  EXPECT_EQ(-575, big_expand_skewport.x());
+  EXPECT_EQ(-575, big_expand_skewport.y());
+  EXPECT_EQ(1650, big_expand_skewport.width());
+  EXPECT_EQ(1650, big_expand_skewport.height());
+  EXPECT_TRUE(big_expand_skewport.Contains(gfx::Rect(-500, -500, 1500, 1500)));
+
+  // Shrink the skewport in all directions.
+  gfx::Rect shrink_viewport =
+      tiling_set->ComputeSkewport(gfx::Rect(0, 0, 100, 100), 1.5, 1.f);
+  EXPECT_EQ(0, shrink_viewport.x());
+  EXPECT_EQ(0, shrink_viewport.y());
+  EXPECT_EQ(100, shrink_viewport.width());
+  EXPECT_EQ(100, shrink_viewport.height());
+
+  // Move the skewport really far in one direction.
+  gfx::Rect move_skewport_far =
+      tiling_set->ComputeSkewport(gfx::Rect(0, 5000, 100, 100), 1.5, 1.f);
+  EXPECT_EQ(0, move_skewport_far.x());
+  EXPECT_EQ(5000, move_skewport_far.y());
+  EXPECT_EQ(100, move_skewport_far.width());
+  EXPECT_EQ(175, move_skewport_far.height());
+  EXPECT_TRUE(move_skewport_far.Contains(gfx::Rect(0, 5000, 100, 100)));
+}
+
+TEST(PictureLayerTilingSetTest, ComputeSkewportExtremeCases) {
+  FakePictureLayerTilingClient client;
+
+  gfx::Size layer_bounds(200, 200);
+  client.SetTileSize(gfx::Size(100, 100));
+  LayerTreeSettings settings;
+  settings.tiling_interest_area_padding = 1000000000;
+  scoped_refptr<FakeRasterSource> raster_source =
+      FakeRasterSource::CreateFilled(layer_bounds);
+  std::unique_ptr<TestablePictureLayerTilingSet> tiling_set =
+      CreateTilingSetWithSettings(&client, settings);
+  tiling_set->AddTiling(1.f, raster_source);
+
+  gfx::Rect viewport1(-1918, 255860, 4010, 2356);
+  gfx::Rect viewport2(-7088, -91738, 14212, 8350);
+  gfx::Rect viewport3(-12730024, -158883296, 24607540, 14454512);
+  double time = 1.0;
+  tiling_set->UpdateTilePriorities(viewport1, 1.f, time, Occlusion(), true);
+  time += 0.016;
+  EXPECT_TRUE(
+      tiling_set->ComputeSkewport(viewport2, time, 1.f).Contains(viewport2));
+  tiling_set->UpdateTilePriorities(viewport2, 1.f, time, Occlusion(), true);
+  time += 0.016;
+  EXPECT_TRUE(
+      tiling_set->ComputeSkewport(viewport3, time, 1.f).Contains(viewport3));
+
+  // Use a tiling with a large scale, so the viewport times the scale no longer
+  // fits into integers, and the viewport is not anywhere close to the tiling.
+  PictureLayerTiling* tiling = tiling_set->AddTiling(1000.f, raster_source);
+  EXPECT_TRUE(tiling_set->TilingsNeedUpdate(viewport3, time));
+  tiling_set->UpdateTilePriorities(viewport3, 1.f, time, Occlusion(), true);
+  EXPECT_TRUE(tiling->GetCurrentVisibleRectForTesting().IsEmpty());
+}
+
+TEST(PictureLayerTilingSetTest, ComputeSkewport) {
+  FakePictureLayerTilingClient client;
+
+  gfx::Rect viewport(0, 0, 100, 100);
+  gfx::Size layer_bounds(200, 200);
+
+  client.SetTileSize(gfx::Size(100, 100));
+
+  scoped_refptr<FakeRasterSource> raster_source =
+      FakeRasterSource::CreateFilled(layer_bounds);
+  std::unique_ptr<TestablePictureLayerTilingSet> tiling_set =
+      CreateTilingSet(&client);
+  tiling_set->AddTiling(1.f, raster_source);
+
+  tiling_set->UpdateTilePriorities(viewport, 1.f, 1.0, Occlusion(), true);
+
+  // Move viewport down 50 pixels in 0.5 seconds.
+  gfx::Rect down_skewport =
+      tiling_set->ComputeSkewport(gfx::Rect(0, 50, 100, 100), 1.5, 1.f);
+
+  EXPECT_EQ(0, down_skewport.x());
+  EXPECT_EQ(50, down_skewport.y());
+  EXPECT_EQ(100, down_skewport.width());
+  EXPECT_EQ(200, down_skewport.height());
+
+  // Shrink viewport.
+  gfx::Rect shrink_skewport =
+      tiling_set->ComputeSkewport(gfx::Rect(25, 25, 50, 50), 1.5, 1.f);
+
+  EXPECT_EQ(25, shrink_skewport.x());
+  EXPECT_EQ(25, shrink_skewport.y());
+  EXPECT_EQ(50, shrink_skewport.width());
+  EXPECT_EQ(50, shrink_skewport.height());
+
+  // Move viewport down 50 and right 10 pixels.
+  gfx::Rect down_right_skewport =
+      tiling_set->ComputeSkewport(gfx::Rect(10, 50, 100, 100), 1.5, 1.f);
+
+  EXPECT_EQ(10, down_right_skewport.x());
+  EXPECT_EQ(50, down_right_skewport.y());
+  EXPECT_EQ(120, down_right_skewport.width());
+  EXPECT_EQ(200, down_right_skewport.height());
+
+  // Move viewport left.
+  gfx::Rect left_skewport =
+      tiling_set->ComputeSkewport(gfx::Rect(-20, 0, 100, 100), 1.5, 1.f);
+
+  EXPECT_EQ(-60, left_skewport.x());
+  EXPECT_EQ(0, left_skewport.y());
+  EXPECT_EQ(140, left_skewport.width());
+  EXPECT_EQ(100, left_skewport.height());
+
+  // Expand viewport in 0.2 seconds.
+  gfx::Rect expanded_skewport =
+      tiling_set->ComputeSkewport(gfx::Rect(-5, -5, 110, 110), 1.2, 1.f);
+
+  EXPECT_EQ(-30, expanded_skewport.x());
+  EXPECT_EQ(-30, expanded_skewport.y());
+  EXPECT_EQ(160, expanded_skewport.width());
+  EXPECT_EQ(160, expanded_skewport.height());
+}
+
+TEST(PictureLayerTilingSetTest, SkewportThroughUpdateTilePriorities) {
+  FakePictureLayerTilingClient client;
+
+  gfx::Rect viewport(0, 0, 100, 100);
+  gfx::Size layer_bounds(200, 200);
+
+  client.SetTileSize(gfx::Size(100, 100));
+
+  scoped_refptr<FakeRasterSource> raster_source =
+      FakeRasterSource::CreateFilled(layer_bounds);
+  std::unique_ptr<TestablePictureLayerTilingSet> tiling_set =
+      CreateTilingSet(&client);
+  tiling_set->AddTiling(1.f, raster_source);
+
+  tiling_set->UpdateTilePriorities(viewport, 1.f, 1.0, Occlusion(), true);
+
+  // Move viewport down 50 pixels in 0.5 seconds.
+  gfx::Rect viewport_50 = gfx::Rect(0, 50, 100, 100);
+  gfx::Rect skewport_50 = tiling_set->ComputeSkewport(viewport_50, 1.5, 1.f);
+
+  EXPECT_EQ(gfx::Rect(0, 50, 100, 200), skewport_50);
+  tiling_set->UpdateTilePriorities(viewport_50, 1.f, 1.5, Occlusion(), true);
+
+  gfx::Rect viewport_100 = gfx::Rect(0, 100, 100, 100);
+  gfx::Rect skewport_100 = tiling_set->ComputeSkewport(viewport_100, 2.0, 1.f);
+
+  EXPECT_EQ(gfx::Rect(0, 100, 100, 200), skewport_100);
+  tiling_set->UpdateTilePriorities(viewport_100, 1.f, 2.0, Occlusion(), true);
+
+  // Advance time, but not the viewport.
+  gfx::Rect result = tiling_set->ComputeSkewport(viewport_100, 2.5, 1.f);
+  // Since the history did advance, we should still get a skewport but a smaller
+  // one.
+  EXPECT_EQ(gfx::Rect(0, 100, 100, 150), result);
+  tiling_set->UpdateTilePriorities(viewport_100, 1.f, 2.5, Occlusion(), true);
+
+  // Advance time again.
+  result = tiling_set->ComputeSkewport(viewport_100, 3.0, 1.f);
+  EXPECT_EQ(viewport_100, result);
+  tiling_set->UpdateTilePriorities(viewport_100, 1.f, 3.0, Occlusion(), true);
+
+  // Ensure we have a skewport.
+  gfx::Rect viewport_150 = gfx::Rect(0, 150, 100, 100);
+  gfx::Rect skewport_150 = tiling_set->ComputeSkewport(viewport_150, 3.5, 1.f);
+  EXPECT_EQ(gfx::Rect(0, 150, 100, 150), skewport_150);
+  tiling_set->UpdateTilePriorities(viewport_150, 1.f, 3.5, Occlusion(), true);
+
+  // Advance the viewport, but not the time.
+  gfx::Rect viewport_200 = gfx::Rect(0, 200, 100, 100);
+  gfx::Rect skewport_200 = tiling_set->ComputeSkewport(viewport_200, 3.5, 1.f);
+  EXPECT_EQ(gfx::Rect(0, 200, 100, 300), skewport_200);
+
+  // Ensure that continued calls with the same value, produce the same skewport.
+  tiling_set->UpdateTilePriorities(viewport_150, 1.f, 3.5, Occlusion(), true);
+  EXPECT_EQ(gfx::Rect(0, 200, 100, 300), skewport_200);
+  tiling_set->UpdateTilePriorities(viewport_150, 1.f, 3.5, Occlusion(), true);
+  EXPECT_EQ(gfx::Rect(0, 200, 100, 300), skewport_200);
+
+  tiling_set->UpdateTilePriorities(viewport_200, 1.f, 3.5, Occlusion(), true);
+
+  // This should never happen, but advance the viewport yet again keeping the
+  // time the same.
+  gfx::Rect viewport_250 = gfx::Rect(0, 250, 100, 100);
+  gfx::Rect skewport_250 = tiling_set->ComputeSkewport(viewport_250, 3.5, 1.f);
+  EXPECT_EQ(viewport_250, skewport_250);
+  tiling_set->UpdateTilePriorities(viewport_250, 1.f, 3.5, Occlusion(), true);
+}
+
+TEST(PictureLayerTilingTest, ViewportDistanceWithScale) {
+  FakePictureLayerTilingClient client;
+
+  gfx::Rect viewport(0, 0, 100, 100);
+  gfx::Size layer_bounds(1500, 1500);
+
+  client.SetTileSize(gfx::Size(10, 10));
+  LayerTreeSettings settings;
+
+  // Tiling at 0.25 scale: this should create 47x47 tiles of size 10x10.
+  // The reason is that each tile has a one pixel border, so tile at (1, 2)
+  // for instance begins at (8, 16) pixels. So tile at (46, 46) will begin at
+  // (368, 368) and extend to the end of 1500 * 0.25 = 375 edge of the
+  // tiling.
+  scoped_refptr<FakeRasterSource> raster_source =
+      FakeRasterSource::CreateFilled(layer_bounds);
+  std::unique_ptr<TestablePictureLayerTilingSet> tiling_set =
+      CreateTilingSet(&client);
+  auto* tiling = tiling_set->AddTiling(0.25f, raster_source);
+  tiling->set_resolution(HIGH_RESOLUTION);
+  gfx::Rect viewport_in_content_space =
+      gfx::ScaleToEnclosedRect(viewport, 0.25f);
+
+  tiling_set->UpdateTilePriorities(viewport, 1.f, 1.0, Occlusion(), true);
+  auto prioritized_tiles = tiling->UpdateAndGetAllPrioritizedTilesForTesting();
+
+  // Compute the soon border.
+  gfx::Rect soon_border_rect_in_content_space =
+      tiling_set->ComputeSoonBorderRect(viewport, 1.f);
+  soon_border_rect_in_content_space =
+      gfx::ScaleToEnclosedRect(soon_border_rect_in_content_space, 0.25f);
+
+  // Sanity checks.
+  for (int i = 0; i < 47; ++i) {
+    for (int j = 0; j < 47; ++j) {
+      EXPECT_TRUE(tiling->TileAt(i, j)) << "i: " << i << " j: " << j;
+    }
+  }
+  for (int i = 0; i < 47; ++i) {
+    EXPECT_FALSE(tiling->TileAt(i, 47)) << "i: " << i;
+    EXPECT_FALSE(tiling->TileAt(47, i)) << "i: " << i;
+  }
+
+  // No movement in the viewport implies that tiles will either be NOW
+  // or EVENTUALLY, with the exception of tiles that are between 0 and 312
+  // pixels away from the viewport, which will be in the SOON bin.
+  bool have_now = false;
+  bool have_eventually = false;
+  bool have_soon = false;
+  for (int i = 0; i < 47; ++i) {
+    for (int j = 0; j < 47; ++j) {
+      Tile* tile = tiling->TileAt(i, j);
+      PrioritizedTile prioritized_tile = prioritized_tiles[tile];
+      TilePriority priority = prioritized_tile.priority();
+
+      gfx::Rect tile_rect = tiling->TilingDataForTesting().TileBounds(i, j);
+      if (viewport_in_content_space.Intersects(tile_rect)) {
+        EXPECT_EQ(TilePriority::NOW, priority.priority_bin);
+        EXPECT_FLOAT_EQ(0.f, priority.distance_to_visible);
+        have_now = true;
+      } else if (soon_border_rect_in_content_space.Intersects(tile_rect)) {
+        EXPECT_EQ(TilePriority::SOON, priority.priority_bin);
+        have_soon = true;
+      } else {
+        EXPECT_EQ(TilePriority::EVENTUALLY, priority.priority_bin);
+        EXPECT_GT(priority.distance_to_visible, 0.f);
+        have_eventually = true;
+      }
+    }
+  }
+
+  EXPECT_TRUE(have_now);
+  EXPECT_TRUE(have_soon);
+  EXPECT_TRUE(have_eventually);
+
+  // Spot check some distances.
+  // Tile at 5, 1 should begin at 41x9 in content space (without borders),
+  // so the distance to a viewport that ends at 25x25 in content space
+  // should be 17 (41 - 25 + 1). In layer space, then that should be
+  // 17 / 0.25 = 68 pixels.
+
+  // We can verify that the content rect (with borders) is one pixel off
+  // 41,9 8x8 on all sides.
+  EXPECT_EQ(tiling->TileAt(5, 1)->content_rect().ToString(), "40,8 10x10");
+
+  TilePriority priority = prioritized_tiles[tiling->TileAt(5, 1)].priority();
+  EXPECT_FLOAT_EQ(68.f, priority.distance_to_visible);
+
+  priority = prioritized_tiles[tiling->TileAt(2, 5)].priority();
+  EXPECT_FLOAT_EQ(68.f, priority.distance_to_visible);
+
+  priority = prioritized_tiles[tiling->TileAt(3, 4)].priority();
+  EXPECT_FLOAT_EQ(40.f, priority.distance_to_visible);
+
+  // Move the viewport down 40 pixels.
+  viewport = gfx::Rect(0, 40, 100, 100);
+  viewport_in_content_space = gfx::ScaleToEnclosedRect(viewport, 0.25f);
+  gfx::Rect skewport_in_content_space =
+      tiling_set->ComputeSkewport(viewport, 2.0, 1.f);
+  skewport_in_content_space =
+      gfx::ScaleToEnclosedRect(skewport_in_content_space, 0.25f);
+
+  // Compute the soon border.
+  soon_border_rect_in_content_space =
+      tiling_set->ComputeSoonBorderRect(viewport, 1.f);
+  soon_border_rect_in_content_space =
+      gfx::ScaleToEnclosedRect(soon_border_rect_in_content_space, 0.25f);
+
+  EXPECT_EQ(0, skewport_in_content_space.x());
+  EXPECT_EQ(10, skewport_in_content_space.y());
+  EXPECT_EQ(25, skewport_in_content_space.width());
+  EXPECT_EQ(35, skewport_in_content_space.height());
+
+  EXPECT_TRUE(tiling_set->TilingsNeedUpdate(viewport, 2.0));
+  tiling_set->UpdateTilePriorities(viewport, 1.f, 2.0, Occlusion(), true);
+  prioritized_tiles = tiling->UpdateAndGetAllPrioritizedTilesForTesting();
+
+  have_now = false;
+  have_eventually = false;
+  have_soon = false;
+
+  // Viewport moved, so we expect to find some NOW tiles, some SOON tiles and
+  // some EVENTUALLY tiles.
+  for (int i = 0; i < 47; ++i) {
+    for (int j = 0; j < 47; ++j) {
+      Tile* tile = tiling->TileAt(i, j);
+      TilePriority priority = prioritized_tiles[tile].priority();
+
+      gfx::Rect tile_rect = tiling->TilingDataForTesting().TileBounds(i, j);
+      if (viewport_in_content_space.Intersects(tile_rect)) {
+        EXPECT_EQ(TilePriority::NOW, priority.priority_bin) << "i: " << i
+                                                            << " j: " << j;
+        EXPECT_FLOAT_EQ(0.f, priority.distance_to_visible) << "i: " << i
+                                                           << " j: " << j;
+        have_now = true;
+      } else if (skewport_in_content_space.Intersects(tile_rect) ||
+                 soon_border_rect_in_content_space.Intersects(tile_rect)) {
+        EXPECT_EQ(TilePriority::SOON, priority.priority_bin) << "i: " << i
+                                                             << " j: " << j;
+        EXPECT_GT(priority.distance_to_visible, 0.f) << "i: " << i
+                                                     << " j: " << j;
+        have_soon = true;
+      } else {
+        EXPECT_EQ(TilePriority::EVENTUALLY, priority.priority_bin)
+            << "i: " << i << " j: " << j;
+        EXPECT_GT(priority.distance_to_visible, 0.f) << "i: " << i
+                                                     << " j: " << j;
+        have_eventually = true;
+      }
+    }
+  }
+
+  EXPECT_TRUE(have_now);
+  EXPECT_TRUE(have_soon);
+  EXPECT_TRUE(have_eventually);
+
+  priority = prioritized_tiles[tiling->TileAt(5, 1)].priority();
+  EXPECT_FLOAT_EQ(68.f, priority.distance_to_visible);
+
+  priority = prioritized_tiles[tiling->TileAt(2, 5)].priority();
+  EXPECT_FLOAT_EQ(28.f, priority.distance_to_visible);
+
+  priority = prioritized_tiles[tiling->TileAt(3, 4)].priority();
+  EXPECT_FLOAT_EQ(4.f, priority.distance_to_visible);
+
+  // Change the underlying layer scale.
+  tiling_set->UpdateTilePriorities(viewport, 2.0f, 3.0, Occlusion(), true);
+  prioritized_tiles = tiling->UpdateAndGetAllPrioritizedTilesForTesting();
+
+  priority = prioritized_tiles[tiling->TileAt(5, 1)].priority();
+  EXPECT_FLOAT_EQ(136.f, priority.distance_to_visible);
+
+  priority = prioritized_tiles[tiling->TileAt(2, 5)].priority();
+  EXPECT_FLOAT_EQ(56.f, priority.distance_to_visible);
+
+  priority = prioritized_tiles[tiling->TileAt(3, 4)].priority();
+  EXPECT_FLOAT_EQ(8.f, priority.distance_to_visible);
+
+  // Test additional scales.
+  tiling = tiling_set->AddTiling(0.2f, raster_source);
+  tiling->set_resolution(HIGH_RESOLUTION);
+  tiling_set->UpdateTilePriorities(viewport, 1.0f, 4.0, Occlusion(), true);
+  prioritized_tiles = tiling->UpdateAndGetAllPrioritizedTilesForTesting();
+
+  priority = prioritized_tiles[tiling->TileAt(5, 1)].priority();
+  EXPECT_FLOAT_EQ(110.f, priority.distance_to_visible);
+
+  priority = prioritized_tiles[tiling->TileAt(2, 5)].priority();
+  EXPECT_FLOAT_EQ(70.f, priority.distance_to_visible);
+
+  priority = prioritized_tiles[tiling->TileAt(3, 4)].priority();
+  EXPECT_FLOAT_EQ(60.f, priority.distance_to_visible);
+
+  tiling_set->UpdateTilePriorities(viewport, 0.5f, 5.0, Occlusion(), true);
+  prioritized_tiles = tiling->UpdateAndGetAllPrioritizedTilesForTesting();
+
+  priority = prioritized_tiles[tiling->TileAt(5, 1)].priority();
+  EXPECT_FLOAT_EQ(55.f, priority.distance_to_visible);
+
+  priority = prioritized_tiles[tiling->TileAt(2, 5)].priority();
+  EXPECT_FLOAT_EQ(35.f, priority.distance_to_visible);
+
+  priority = prioritized_tiles[tiling->TileAt(3, 4)].priority();
+  EXPECT_FLOAT_EQ(30.f, priority.distance_to_visible);
+}
+
+TEST(PictureLayerTilingTest, InvalidateAfterComputeTilePriorityRects) {
+  FakePictureLayerTilingClient pending_client;
+  pending_client.SetTileSize(gfx::Size(100, 100));
+
+  scoped_refptr<FakeRasterSource> raster_source =
+      FakeRasterSource::CreateFilled(gfx::Size(100, 100));
+  std::unique_ptr<TestablePictureLayerTilingSet> tiling_set =
+      CreateTilingSet(&pending_client);
+  auto* pending_tiling = tiling_set->AddTiling(1.f, raster_source);
+  pending_tiling->set_resolution(HIGH_RESOLUTION);
+
+  // Ensure that we can compute tile priority rects, invalidate, and compute the
+  // rects again. It is important that the second compute tile priority rects
+  // return true, indicating that things have changed (since invalidation has
+  // changed things). This causes PrepareTiles to be properly scheduled. If the
+  // second ComputeTilePriorityRects returns false, then we assume that
+  // PrepareTiles isn't needed and we signal that we're ready to draw
+  // immediately, which can cause visual glitches.
+  //
+  // This can happen we if we process an impl frame deadline before processing a
+  // commit. That is, when we draw we ComputeTilePriorityRects. If we process
+  // the commit afterwards, it would use the same timestamp and sometimes would
+  // use the same viewport to compute tile priority rects again.
+  double time = 1.;
+  gfx::Rect viewport(0, 0, 100, 100);
+  EXPECT_TRUE(
+      tiling_set->UpdateTilePriorities(viewport, 1.f, time, Occlusion(), true));
+  EXPECT_FALSE(
+      tiling_set->UpdateTilePriorities(viewport, 1.f, time, Occlusion(), true));
+
+  // This will invalidate tilings.
+  tiling_set->UpdateRasterSourceDueToLCDChange(raster_source, Region());
+
+  EXPECT_TRUE(
+      tiling_set->UpdateTilePriorities(viewport, 1.f, time, Occlusion(), true));
+}
+
 }  // namespace
 }  // namespace cc