cc: Update effect_tree backface visibility when transform is updated.

cc/trees/layer_tree_host_common_unittest.cc

Index: cc/trees/layer_tree_host_common_unittest.cc
diff --git a/cc/trees/layer_tree_host_common_unittest.cc b/cc/trees/layer_tree_host_common_unittest.cc
index 77b1c68ecfdbc6706f62c28daa671f52dcecd8b2..eba5dd076431638eb82b15ebd5c3e516e85098fa 100644
--- a/cc/trees/layer_tree_host_common_unittest.cc
+++ b/cc/trees/layer_tree_host_common_unittest.cc
@@ -6391,6 +6391,64 @@ TEST_F(LayerTreeHostCommonTest, DoNotIncludeBackfaceInvisibleLayers) {
   EXPECT_FALSE(grand_child->use_local_transform_for_backface_visibility());
 }
 
+TEST_F(LayerTreeHostCommonTest, TransformAnimationUpdatesBackfaceVisibility) {
+  LayerImpl* root = root_layer();
+  LayerImpl* back_facing = AddChild<LayerImpl>(root);
+  LayerImpl* render_surface1 = AddChild<LayerImpl>(back_facing);
+  LayerImpl* render_surface2 = AddChild<LayerImpl>(back_facing);
+
+  gfx::Transform identity_transform;
+  gfx::Transform rotateAboutY;

[ajuma, 2016/05/19 17:13:10]

nit: rotate_about_y

+  rotateAboutY.RotateAboutYAxis(180.0);
+  SetLayerPropertiesForTesting(root, identity_transform, gfx::Point3F(),
+                               gfx::PointF(), gfx::Size(50, 50), true, false,
+                               true);
+  SetLayerPropertiesForTesting(back_facing, rotateAboutY, gfx::Point3F(),
+                               gfx::PointF(), gfx::Size(50, 50), true, false,
+                               false);
+  SetLayerPropertiesForTesting(render_surface1, identity_transform,
+                               gfx::Point3F(), gfx::PointF(), gfx::Size(30, 30),
+                               false, true, true);
+  SetLayerPropertiesForTesting(render_surface2, identity_transform,
+                               gfx::Point3F(), gfx::PointF(), gfx::Size(30, 30),
+                               false, true, true);
+
+  root->test_properties()->should_flatten_transform = false;
+  root->Set3dSortingContextId(1);
+  back_facing->Set3dSortingContextId(1);
+  back_facing->test_properties()->should_flatten_transform = false;
+  render_surface1->Set3dSortingContextId(1);
+  render_surface1->test_properties()->double_sided = false;
+  render_surface2->Set3dSortingContextId(1);
+  render_surface2->test_properties()->double_sided = false;

[ajuma, 2016/05/19 17:13:09]

SetLayerPropertiesForTesting already takes arguments (flatten_transform and
is_3d_sorted) equivalent to should_flatten_transform and whether the layer has
sorting context id 1, so these can be set as part of the
SetLayerPropertiesForTesting calls above.

[sunxd, 2016/05/19 17:59:56]

Done.

+
+  ExecuteCalculateDrawProperties(root);
+
+  const EffectTree& tree =
+      root->layer_tree_impl()->property_trees()->effect_tree;
+  EXPECT_TRUE(tree.Node(render_surface1->effect_tree_index())
+                  ->data.hidden_by_backface_visibility);
+  EXPECT_TRUE(tree.Node(render_surface2->effect_tree_index())
+                  ->data.hidden_by_backface_visibility);
+
+  back_facing->OnTransformAnimated(identity_transform);
+  render_surface2->OnTransformAnimated(rotateAboutY);
+  draw_property_utils::UpdatePropertyTrees(
+      root->layer_tree_impl()->property_trees(), true);

[ajuma, 2016/05/19 17:13:10]

Calling ExecuteCalculateDrawProperties instead is more similar to what happens
outside of test code.

[sunxd, 2016/05/19 17:59:56]

A problem of calling ExecuteCDP here is that UpdatePropertyTrees isn't called by
the function.

But there is also a place where we can add force effect tree update in
ComputeVisibleRects. Both a single fix in UpdatePropertyTrees and a single fix
in ComputeVisibleRects can fix the bug.

+  EXPECT_FALSE(tree.Node(render_surface1->effect_tree_index())
+                   ->data.hidden_by_backface_visibility);
+  EXPECT_TRUE(tree.Node(render_surface2->effect_tree_index())
+                  ->data.hidden_by_backface_visibility);
+
+  render_surface1->OnTransformAnimated(rotateAboutY);
+  draw_property_utils::UpdatePropertyTrees(
+      root->layer_tree_impl()->property_trees(), true);

[ajuma, 2016/05/19 17:13:10]

Call ExcecuteCalculateDrawProperties here.

+  EXPECT_TRUE(tree.Node(render_surface1->effect_tree_index())
+                  ->data.hidden_by_backface_visibility);
+  EXPECT_TRUE(tree.Node(render_surface2->effect_tree_index())
+                  ->data.hidden_by_backface_visibility);
+}
+
 TEST_F(LayerTreeHostCommonTest, ClippedByScrollParent) {
   // Checks that the simple case (being clipped by a scroll parent that would
   // have been processed before you anyhow) results in the right clips.