cc : Use effect node data to determine which opacity wins at commit.

cc/trees/layer_tree_host_unittest.cc

Index: cc/trees/layer_tree_host_unittest.cc
diff --git a/cc/trees/layer_tree_host_unittest.cc b/cc/trees/layer_tree_host_unittest.cc
index 34868a4c729259963f0787a8f16f6c542edae6bb..23dd261ff2f272c260b82cb3e0d7edb96e03691f 100644
--- a/cc/trees/layer_tree_host_unittest.cc
+++ b/cc/trees/layer_tree_host_unittest.cc
@@ -835,6 +835,64 @@ class LayerTreeHostTestPropertyTreesChangedSync : public LayerTreeHostTest {
 
 SINGLE_THREAD_TEST_F(LayerTreeHostTestPropertyTreesChangedSync);
 
+class LayerTreeHostTestEffectTreeSync : public LayerTreeHostTest {
+ protected:
+  void SetupTree() override {
+    root_ = Layer::Create();
+    layer_tree_host()->SetRootLayer(root_);
+    LayerTreeHostTest::SetupTree();
+  }
+
+  void BeginTest() override { PostSetNeedsCommitToMainThread(); }
+
+  void DidCommit() override {
+    EffectTree& effect_tree = layer_tree_host()->property_trees()->effect_tree;
+    EffectNode* node = effect_tree.Node(root_->effect_tree_index());
+    switch (layer_tree_host()->source_frame_number()) {
+      case 1:
+        root_->SetOpacity(0.5f);
+        node->data.is_currently_animating_opacity = true;
+        // Changing opacity forces us to rebuild proeprty trees. We want to

[ajuma, 2016/05/11 17:22:28]

Hmm! If the layer whose opacity changed already has an effect node, we shouldn't
need to rebuild. But that's unrelated to this CL so can be fixed in follow-up.

Also, s/proeprty/property

[jaydasika, 2016/05/11 18:08:45]

Setting opacity on a layer doesn't set opacity on the effect tree immediately.
Instead, it depends on the rebuild of property trees to do that. So, I have
changed this test to change the opacity on the effect node directly (so that the
rebuild in case 2 can be removed). But I agree, we shouldn't be rebuilding if
the layer already has an effect node.

+        // prevent that here as that will reset is_currently_animating_opacity.
+        layer_tree_host()->property_trees()->needs_rebuild = false;
+        break;
+      case 2:
+        // Forcing rebuild of property trees will reset
+        // is_currently_animating_opacity.
+        layer_tree_host()->property_trees()->needs_rebuild = true;

[ajuma, 2016/05/11 17:22:28]

How about directly setting is_currently_animating to false instead of
rebuilding?

[jaydasika, 2016/05/11 18:08:45]

Done.

+        root_->SetNeedsPushProperties();
+        break;
+    }
+  }
+
+  void CommitCompleteOnThread(LayerTreeHostImpl* impl) override {
+    EffectTree& effect_tree = impl->sync_tree()->property_trees()->effect_tree;
+    EffectNode* node =
+        effect_tree.Node(impl->sync_tree()->root_layer()->effect_tree_index());
+    switch (impl->sync_tree()->source_frame_number()) {
+      case 0:
+        impl->sync_tree()->root_layer()->OnOpacityAnimated(0.75f);
+        PostSetNeedsCommitToMainThread();
+        break;
+      case 1:
+        EXPECT_EQ(node->data.opacity, 0.75f);
+        PostSetNeedsCommitToMainThread();
+        break;
+      case 2:
+        EXPECT_EQ(node->data.opacity, 0.5f);
+        EndTest();
+        break;
+    }
+  }
+
+  void AfterTest() override {}
+
+ private:
+  scoped_refptr<Layer> root_;
+};
+
+SINGLE_AND_MULTI_THREAD_TEST_F(LayerTreeHostTestEffectTreeSync);
+
 // Verify damage status is updated even when the transform tree doesn't need
 // to be updated at draw time.
 class LayerTreeHostTestTransformTreeDamageIsUpdated : public LayerTreeHostTest {