Add operator!= to PlatformThreadRef

base/threading/platform_thread.h

Index: base/threading/platform_thread.h
diff --git a/base/threading/platform_thread.h b/base/threading/platform_thread.h
index 0b34cce25f957db94cd19d119029e4e74a90933d..511298ee9d41115816c2fbd476e9578893f6bf82 100644
--- a/base/threading/platform_thread.h
+++ b/base/threading/platform_thread.h
@@ -59,6 +59,8 @@ class PlatformThreadRef {
     return id_ == other.id_;
   }
 
+  bool operator!=(PlatformThreadRef other) const { return id_ != other.id_; }
+
   bool is_null() const {
     return id_ == 0;
   }