cc: Require high res tiles to activate when active twin has different bounds.

This is required to prevent checkerboarding and low-res tiles from
being visible when the size of a layer is increased.

BUG=372287
TEST=cc_unittess --gtest_filter=PictureLayerImplTest.HighResRequiredWhenActiveHasDifferentBounds
R=enne

Review URL: https://codereview.chromium.org/288783002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@270514 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 19 insertions, 0 deletions

diff --git a/cc/layers/picture_layer_impl_unittest.cc b/cc/layers/picture_layer_impl_unittest.cc
index 590560f..bdbe172 100644
--- a/cc/layers/picture_layer_impl_unittest.cc
+++ b/cc/layers/picture_layer_impl_unittest.cc
@@ -1609,6 +1609,25 @@ TEST_F(PictureLayerImplTest, HighResRequiredIfActiveCantHaveTiles) {
   AssertNoTilesRequired(pending_layer_->LowResTiling());
 }
 
+TEST_F(PictureLayerImplTest, HighResRequiredWhenActiveHasDifferentBounds) {
+  gfx::Size layer_bounds(200, 200);
+  gfx::Size tile_size(100, 100);
+  SetupDefaultTreesWithFixedTileSize(layer_bounds, tile_size);
+
+  gfx::Size pending_layer_bounds(400, 400);
+  pending_layer_->SetBounds(pending_layer_bounds);
+
+  CreateHighLowResAndSetAllTilesVisible();
+
+  active_layer_->SetAllTilesReady();
+
+  // Since the active layer has different bounds, the pending layer needs all
+  // high res tiles in order to activate.
+  pending_layer_->MarkVisibleResourcesAsRequired();
+  AssertAllTilesRequired(pending_layer_->HighResTiling());
+  AssertNoTilesRequired(pending_layer_->LowResTiling());
+}
+
 TEST_F(PictureLayerImplTest, ActivateUninitializedLayer) {
   gfx::Size tile_size(100, 100);
   gfx::Size layer_bounds(400, 400);