Update from chromium https://crrev.com/302282

cc/resources/resource_pool.h

Index: cc/resources/resource_pool.h
diff --git a/cc/resources/resource_pool.h b/cc/resources/resource_pool.h
index 5f481e986a1a86de14318eac7ad8ea3a40be3864..e1ee35aa72c6039c01a6ae8e71eb3f4832ffe524 100644
--- a/cc/resources/resource_pool.h
+++ b/cc/resources/resource_pool.h
@@ -34,7 +34,10 @@ class CC_EXPORT ResourcePool {
                               size_t max_resource_count);
 
   void ReduceResourceUsage();
-  void CheckBusyResources();
+  // This might block if |wait_if_needed| is true and one of the currently
+  // busy resources has a read lock fence that needs to be waited upon before
+  // it can be locked for write again.
+  void CheckBusyResources(bool wait_if_needed);
 
   size_t total_memory_usage_bytes() const { return memory_usage_bytes_; }
   size_t acquired_memory_usage_bytes() const {
@@ -44,6 +47,7 @@ class CC_EXPORT ResourcePool {
   size_t acquired_resource_count() const {
     return resource_count_ - unused_resources_.size();
   }
+  size_t busy_resource_count() const { return busy_resources_.size(); }
 
   ResourceFormat resource_format() const { return format_; }