Update from https://crrev.com/312398

cc/animation/animation_id_provider.cc

Index: cc/animation/animation_id_provider.cc
diff --git a/cc/animation/animation_id_provider.cc b/cc/animation/animation_id_provider.cc
index 5c7afb6d98c7ae4fa8a4360b22681456d6efd5bd..caefdb8fee588a5ae3f792861547e806b05604a2 100644
--- a/cc/animation/animation_id_provider.cc
+++ b/cc/animation/animation_id_provider.cc
@@ -2,18 +2,22 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
+#include "base/atomic_sequence_num.h"
 #include "cc/animation/animation_id_provider.h"
 
 namespace cc {
 
+base::StaticAtomicSequenceNumber g_next_animation_id;
+base::StaticAtomicSequenceNumber g_next_group_id;
+
 int AnimationIdProvider::NextAnimationId() {
-  static int next_animation_id = 1;
-  return next_animation_id++;
+  // Animation IDs start from 1.
+  return g_next_animation_id.GetNext() + 1;
 }
 
 int AnimationIdProvider::NextGroupId() {
-  static int next_group_id = 1;
-  return next_group_id++;
+  // Animation group IDs start from 1.
+  return g_next_group_id.GetNext() + 1;
 }
 
 }  // namespace cc