cc: Fix animated filter render surface check

The render surface calculation wasn't taking into account animated
filters.  These are animations which will eventually set a filter, but
the filters on the layer are empty at render surface calculation time.

This is just a missed case in render surface calculation, as it used
to be handled naturally on the compositor thread after the filter got
added.

R=vollick@chromium.org
BUG=461180

Review URL: https://codereview.chromium.org/957703004

Cr-Commit-Position: refs/heads/master@{#318138}

cc/trees/layer_tree_host_common.cc

@@ -591,6 +591,13 @@ static bool SubtreeShouldRenderToSeparateSurface(
     return true;
   }
 
+  // If the layer will use a CSS filter.  In this case, the animation
+  // will start and add a filter to this layer, so it needs a surface.
+  if (layer->FilterIsAnimating()) {
+    DCHECK(!is_root);
+    return true;
+  }
+
   int num_descendants_that_draw_content =
       layer->NumDescendantsThatDrawContent();
 
@@ -1198,20 +1205,22 @@ struct PreCalculateMetaInformationRecursiveData {
   }
 };
 
-static bool ValidateRenderSurface(LayerImpl* layer) {
+static void ValidateRenderSurface(LayerImpl* layer) {
   // This test verifies that there are no cases where a LayerImpl needs
   // a render surface, but doesn't have one.
   if (layer->render_surface())
-    return true;
+    return;
 
-  return layer->filters().IsEmpty() && layer->background_filters().IsEmpty() &&
-         !layer->mask_layer() && !layer->replica_layer() &&
-         !IsRootLayer(layer) && !layer->is_root_for_isolated_group() &&
-         !layer->HasCopyRequest();
+  DCHECK(layer->filters().IsEmpty()) << "layer: " << layer->id();
+  DCHECK(layer->background_filters().IsEmpty()) << "layer: " << layer->id();
+  DCHECK(!layer->mask_layer()) << "layer: " << layer->id();
+  DCHECK(!layer->replica_layer()) << "layer: " << layer->id();
+  DCHECK(!IsRootLayer(layer)) << "layer: " << layer->id();
+  DCHECK(!layer->is_root_for_isolated_group()) << "layer: " << layer->id();
+  DCHECK(!layer->HasCopyRequest()) << "layer: " << layer->id();
 }
 
-static bool ValidateRenderSurface(Layer* layer) {
-  return true;
+static void ValidateRenderSurface(Layer* layer) {
 }
 
 // Recursively walks the layer tree to compute any information that is needed
@@ -1220,7 +1229,7 @@ template <typename LayerType>
 static void PreCalculateMetaInformation(
     LayerType* layer,
     PreCalculateMetaInformationRecursiveData* recursive_data) {
-  DCHECK(ValidateRenderSurface(layer));
+  ValidateRenderSurface(layer);
 
   layer->draw_properties().sorted_for_recursion = false;
   layer->draw_properties().has_child_with_a_scroll_parent = false;

cc/trees/layer_tree_host_common_unittest.cc

@@ -8775,5 +8775,42 @@ TEST_F(LayerTreeHostCommonTest, VisibleContentRectForAnimatedLayer) {
   EXPECT_FALSE(animated->visible_rect_from_property_trees().IsEmpty());
 }
 
+// Verify that having an animated filter (but no current filter, as these
+// are mutually exclusive) correctly creates a render surface.
+TEST_F(LayerTreeHostCommonTest, AnimatedFilterCreatesRenderSurface) {
+  scoped_refptr<Layer> root = Layer::Create();
+  scoped_refptr<Layer> child = Layer::Create();
+  scoped_refptr<Layer> grandchild = Layer::Create();
+  root->AddChild(child);
+  child->AddChild(grandchild);
+
+  gfx::Transform identity_transform;
+  SetLayerPropertiesForTesting(root.get(), identity_transform, gfx::Point3F(),
+                               gfx::PointF(), gfx::Size(50, 50), true, false);
+  SetLayerPropertiesForTesting(child.get(), identity_transform, gfx::Point3F(),
+                               gfx::PointF(), gfx::Size(50, 50), true, false);
+  SetLayerPropertiesForTesting(grandchild.get(), identity_transform,
+                               gfx::Point3F(), gfx::PointF(), gfx::Size(50, 50),
+                               true, false);
+  scoped_ptr<FakeLayerTreeHost> host(CreateFakeLayerTreeHost());
+  host->SetRootLayer(root);
+
+  AddAnimatedFilterToLayer(child.get(), 10.0, 0.1f, 0.2f);
+
+  ExecuteCalculateDrawProperties(root.get());
+
+  EXPECT_TRUE(root->render_surface());
+  EXPECT_TRUE(child->render_surface());
+  EXPECT_FALSE(grandchild->render_surface());
+
+  EXPECT_TRUE(root->filters().IsEmpty());
+  EXPECT_TRUE(child->filters().IsEmpty());
+  EXPECT_TRUE(grandchild->filters().IsEmpty());
+
+  EXPECT_FALSE(root->FilterIsAnimating());
+  EXPECT_TRUE(child->FilterIsAnimating());
+  EXPECT_FALSE(grandchild->FilterIsAnimating());
+}
+
 }  // namespace
 }  // namespace cc