cc : Store surface layer ids on LayerTreeHost and push them at commit

cc/layers/surface_layer_unittest.cc

Index: cc/layers/surface_layer_unittest.cc
diff --git a/cc/layers/surface_layer_unittest.cc b/cc/layers/surface_layer_unittest.cc
index 4c354a7a5f6100ddd6a008a9972d3b2b2ab9aaab..ff34ffd6dd20d061fa9533d901baa45d394efae5 100644
--- a/cc/layers/surface_layer_unittest.cc
+++ b/cc/layers/surface_layer_unittest.cc
@@ -173,7 +173,26 @@ TEST_F(SurfaceLayerTest, SurfaceInfoPushProperties) {
                 LocalSurfaceId(2, base::UnguessableToken::Create())),
       2.f, gfx::Size(10, 10));
   layer->SetFallbackSurfaceInfo(fallback_info);
-  layer->PushPropertiesTo(layer_impl.get());
+
+  // Verify that surface layer ids are recorded on the layer tree host and need
+  // to be pushed.
+  EXPECT_TRUE(layer_tree_host_->needs_surface_ids_sync());
+  EXPECT_EQ(layer_tree_host_->SurfaceLayerIds().size(), 1u);
+
+  // Verify that pending tree has no surface ids already.
+  EXPECT_FALSE(host_impl_.pending_tree()->needs_surface_ids_sync());
+  EXPECT_EQ(host_impl_.pending_tree()->SurfaceLayerIds().size(), 0u);
+
+  TreeSynchronizer::PushLayerProperties(layer_tree_host_.get(),
+                                        host_impl_.pending_tree());
+
+  // Verify that pending tree received the surface ids and also has
+  // needs_surface_ids_sync set to true as it needs to sync with active tree.
+  EXPECT_TRUE(host_impl_.pending_tree()->needs_surface_ids_sync());
+  EXPECT_EQ(host_impl_.pending_tree()->SurfaceLayerIds().size(), 1u);
+
+  // Verify we have reset the state on layer tree host.
+  EXPECT_FALSE(layer_tree_host_->needs_surface_ids_sync());
 
   // Verify that the primary SurfaceInfo stays the same and the new fallback
   // SurfaceInfo is pushed through.